diff --git a/accounts/abi/bind/backend.go b/accounts/abi/bind/backend.go
index 91e005f0a3..9c3da8e695 100644
--- a/accounts/abi/bind/backend.go
+++ b/accounts/abi/bind/backend.go
@@ -17,13 +17,13 @@
 package bind
 
 import (
+	"context"
 	"errors"
 	"math/big"
 
 	"github.com/ubiq/go-ubiq"
 	"github.com/ubiq/go-ubiq/common"
 	"github.com/ubiq/go-ubiq/core/types"
-	"golang.org/x/net/context"
 )
 
 var (
diff --git a/accounts/abi/bind/backends/simulated.go b/accounts/abi/bind/backends/simulated.go
index 772c50cadf..9b47980845 100644
--- a/accounts/abi/bind/backends/simulated.go
+++ b/accounts/abi/bind/backends/simulated.go
@@ -17,6 +17,7 @@
 package backends
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"math/big"
@@ -32,7 +33,6 @@ import (
 	"github.com/ubiq/go-ubiq/ethdb"
 	"github.com/ubiq/go-ubiq/event"
 	"github.com/ubiq/go-ubiq/params"
-	"golang.org/x/net/context"
 )
 
 // Default chain configuration which sets homestead phase at block 0 (i.e. no frontier)
diff --git a/accounts/abi/bind/base.go b/accounts/abi/bind/base.go
index 9fcee75f24..9fe2cf131c 100644
--- a/accounts/abi/bind/base.go
+++ b/accounts/abi/bind/base.go
@@ -17,6 +17,7 @@
 package bind
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"math/big"
@@ -26,7 +27,6 @@ import (
 	"github.com/ubiq/go-ubiq/common"
 	"github.com/ubiq/go-ubiq/core/types"
 	"github.com/ubiq/go-ubiq/crypto"
-	"golang.org/x/net/context"
 )
 
 // SignerFn is a signer function callback when a contract requires a method to
diff --git a/accounts/abi/bind/util.go b/accounts/abi/bind/util.go
index 0e74c62f2c..4f9f7fdd8a 100644
--- a/accounts/abi/bind/util.go
+++ b/accounts/abi/bind/util.go
@@ -17,6 +17,7 @@
 package bind
 
 import (
+	"context"
 	"fmt"
 	"time"
 
@@ -24,7 +25,6 @@ import (
 	"github.com/ubiq/go-ubiq/core/types"
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
-	"golang.org/x/net/context"
 )
 
 // WaitMined waits for tx to be mined on the blockchain.
diff --git a/accounts/abi/bind/util_test.go b/accounts/abi/bind/util_test.go
index f304dcbc38..5789ec0473 100644
--- a/accounts/abi/bind/util_test.go
+++ b/accounts/abi/bind/util_test.go
@@ -17,6 +17,7 @@
 package bind_test
 
 import (
+	"context"
 	"math/big"
 	"testing"
 	"time"
@@ -27,7 +28,6 @@ import (
 	"github.com/ubiq/go-ubiq/core"
 	"github.com/ubiq/go-ubiq/core/types"
 	"github.com/ubiq/go-ubiq/crypto"
-	"golang.org/x/net/context"
 )
 
 var testKey, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
diff --git a/accounts/usbwallet/ledger_wallet.go b/accounts/usbwallet/ledger_wallet.go
index a91ef56405..01609f895d 100644
--- a/accounts/usbwallet/ledger_wallet.go
+++ b/accounts/usbwallet/ledger_wallet.go
@@ -21,6 +21,7 @@
 package usbwallet
 
 import (
+	"context"
 	"encoding/binary"
 	"encoding/hex"
 	"errors"
@@ -38,7 +39,6 @@ import (
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
 	"github.com/ubiq/go-ubiq/rlp"
-	"golang.org/x/net/context"
 )
 
 // Maximum time between wallet health checks to detect USB unplugs.
diff --git a/build/_vendor/src/golang.org/x/net/LICENSE b/build/_vendor/src/golang.org/x/net/LICENSE
deleted file mode 100644
index 6a66aea5ea..0000000000
--- a/build/_vendor/src/golang.org/x/net/LICENSE
+++ /dev/null
@@ -1,27 +0,0 @@
-Copyright (c) 2009 The Go Authors. All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/build/_vendor/src/golang.org/x/net/context/context.go b/build/_vendor/src/golang.org/x/net/context/context.go
deleted file mode 100644
index 134654cf7e..0000000000
--- a/build/_vendor/src/golang.org/x/net/context/context.go
+++ /dev/null
@@ -1,156 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package context defines the Context type, which carries deadlines,
-// cancelation signals, and other request-scoped values across API boundaries
-// and between processes.
-//
-// Incoming requests to a server should create a Context, and outgoing calls to
-// servers should accept a Context.  The chain of function calls between must
-// propagate the Context, optionally replacing it with a modified copy created
-// using WithDeadline, WithTimeout, WithCancel, or WithValue.
-//
-// Programs that use Contexts should follow these rules to keep interfaces
-// consistent across packages and enable static analysis tools to check context
-// propagation:
-//
-// Do not store Contexts inside a struct type; instead, pass a Context
-// explicitly to each function that needs it.  The Context should be the first
-// parameter, typically named ctx:
-//
-// 	func DoSomething(ctx context.Context, arg Arg) error {
-// 		// ... use ctx ...
-// 	}
-//
-// Do not pass a nil Context, even if a function permits it.  Pass context.TODO
-// if you are unsure about which Context to use.
-//
-// Use context Values only for request-scoped data that transits processes and
-// APIs, not for passing optional parameters to functions.
-//
-// The same Context may be passed to functions running in different goroutines;
-// Contexts are safe for simultaneous use by multiple goroutines.
-//
-// See http://blog.golang.org/context for example code for a server that uses
-// Contexts.
-package context // import "golang.org/x/net/context"
-
-import "time"
-
-// A Context carries a deadline, a cancelation signal, and other values across
-// API boundaries.
-//
-// Context's methods may be called by multiple goroutines simultaneously.
-type Context interface {
-	// Deadline returns the time when work done on behalf of this context
-	// should be canceled.  Deadline returns ok==false when no deadline is
-	// set.  Successive calls to Deadline return the same results.
-	Deadline() (deadline time.Time, ok bool)
-
-	// Done returns a channel that's closed when work done on behalf of this
-	// context should be canceled.  Done may return nil if this context can
-	// never be canceled.  Successive calls to Done return the same value.
-	//
-	// WithCancel arranges for Done to be closed when cancel is called;
-	// WithDeadline arranges for Done to be closed when the deadline
-	// expires; WithTimeout arranges for Done to be closed when the timeout
-	// elapses.
-	//
-	// Done is provided for use in select statements:
-	//
-	//  // Stream generates values with DoSomething and sends them to out
-	//  // until DoSomething returns an error or ctx.Done is closed.
-	//  func Stream(ctx context.Context, out chan<- Value) error {
-	//  	for {
-	//  		v, err := DoSomething(ctx)
-	//  		if err != nil {
-	//  			return err
-	//  		}
-	//  		select {
-	//  		case <-ctx.Done():
-	//  			return ctx.Err()
-	//  		case out <- v:
-	//  		}
-	//  	}
-	//  }
-	//
-	// See http://blog.golang.org/pipelines for more examples of how to use
-	// a Done channel for cancelation.
-	Done() <-chan struct{}
-
-	// Err returns a non-nil error value after Done is closed.  Err returns
-	// Canceled if the context was canceled or DeadlineExceeded if the
-	// context's deadline passed.  No other values for Err are defined.
-	// After Done is closed, successive calls to Err return the same value.
-	Err() error
-
-	// Value returns the value associated with this context for key, or nil
-	// if no value is associated with key.  Successive calls to Value with
-	// the same key returns the same result.
-	//
-	// Use context values only for request-scoped data that transits
-	// processes and API boundaries, not for passing optional parameters to
-	// functions.
-	//
-	// A key identifies a specific value in a Context.  Functions that wish
-	// to store values in Context typically allocate a key in a global
-	// variable then use that key as the argument to context.WithValue and
-	// Context.Value.  A key can be any type that supports equality;
-	// packages should define keys as an unexported type to avoid
-	// collisions.
-	//
-	// Packages that define a Context key should provide type-safe accessors
-	// for the values stores using that key:
-	//
-	// 	// Package user defines a User type that's stored in Contexts.
-	// 	package user
-	//
-	// 	import "golang.org/x/net/context"
-	//
-	// 	// User is the type of value stored in the Contexts.
-	// 	type User struct {...}
-	//
-	// 	// key is an unexported type for keys defined in this package.
-	// 	// This prevents collisions with keys defined in other packages.
-	// 	type key int
-	//
-	// 	// userKey is the key for user.User values in Contexts.  It is
-	// 	// unexported; clients use user.NewContext and user.FromContext
-	// 	// instead of using this key directly.
-	// 	var userKey key = 0
-	//
-	// 	// NewContext returns a new Context that carries value u.
-	// 	func NewContext(ctx context.Context, u *User) context.Context {
-	// 		return context.WithValue(ctx, userKey, u)
-	// 	}
-	//
-	// 	// FromContext returns the User value stored in ctx, if any.
-	// 	func FromContext(ctx context.Context) (*User, bool) {
-	// 		u, ok := ctx.Value(userKey).(*User)
-	// 		return u, ok
-	// 	}
-	Value(key interface{}) interface{}
-}
-
-// Background returns a non-nil, empty Context. It is never canceled, has no
-// values, and has no deadline.  It is typically used by the main function,
-// initialization, and tests, and as the top-level Context for incoming
-// requests.
-func Background() Context {
-	return background
-}
-
-// TODO returns a non-nil, empty Context.  Code should use context.TODO when
-// it's unclear which Context to use or it is not yet available (because the
-// surrounding function has not yet been extended to accept a Context
-// parameter).  TODO is recognized by static analysis tools that determine
-// whether Contexts are propagated correctly in a program.
-func TODO() Context {
-	return todo
-}
-
-// A CancelFunc tells an operation to abandon its work.
-// A CancelFunc does not wait for the work to stop.
-// After the first call, subsequent calls to a CancelFunc do nothing.
-type CancelFunc func()
diff --git a/build/_vendor/src/golang.org/x/net/context/go17.go b/build/_vendor/src/golang.org/x/net/context/go17.go
deleted file mode 100644
index f8cda19ada..0000000000
--- a/build/_vendor/src/golang.org/x/net/context/go17.go
+++ /dev/null
@@ -1,72 +0,0 @@
-// Copyright 2016 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build go1.7
-
-package context
-
-import (
-	"context" // standard library's context, as of Go 1.7
-	"time"
-)
-
-var (
-	todo       = context.TODO()
-	background = context.Background()
-)
-
-// Canceled is the error returned by Context.Err when the context is canceled.
-var Canceled = context.Canceled
-
-// DeadlineExceeded is the error returned by Context.Err when the context's
-// deadline passes.
-var DeadlineExceeded = context.DeadlineExceeded
-
-// WithCancel returns a copy of parent with a new Done channel. The returned
-// context's Done channel is closed when the returned cancel function is called
-// or when the parent context's Done channel is closed, whichever happens first.
-//
-// Canceling this context releases resources associated with it, so code should
-// call cancel as soon as the operations running in this Context complete.
-func WithCancel(parent Context) (ctx Context, cancel CancelFunc) {
-	ctx, f := context.WithCancel(parent)
-	return ctx, CancelFunc(f)
-}
-
-// WithDeadline returns a copy of the parent context with the deadline adjusted
-// to be no later than d.  If the parent's deadline is already earlier than d,
-// WithDeadline(parent, d) is semantically equivalent to parent.  The returned
-// context's Done channel is closed when the deadline expires, when the returned
-// cancel function is called, or when the parent context's Done channel is
-// closed, whichever happens first.
-//
-// Canceling this context releases resources associated with it, so code should
-// call cancel as soon as the operations running in this Context complete.
-func WithDeadline(parent Context, deadline time.Time) (Context, CancelFunc) {
-	ctx, f := context.WithDeadline(parent, deadline)
-	return ctx, CancelFunc(f)
-}
-
-// WithTimeout returns WithDeadline(parent, time.Now().Add(timeout)).
-//
-// Canceling this context releases resources associated with it, so code should
-// call cancel as soon as the operations running in this Context complete:
-//
-// 	func slowOperationWithTimeout(ctx context.Context) (Result, error) {
-// 		ctx, cancel := context.WithTimeout(ctx, 100*time.Millisecond)
-// 		defer cancel()  // releases resources if slowOperation completes before timeout elapses
-// 		return slowOperation(ctx)
-// 	}
-func WithTimeout(parent Context, timeout time.Duration) (Context, CancelFunc) {
-	return WithDeadline(parent, time.Now().Add(timeout))
-}
-
-// WithValue returns a copy of parent in which the value associated with key is
-// val.
-//
-// Use context Values only for request-scoped data that transits processes and
-// APIs, not for passing optional parameters to functions.
-func WithValue(parent Context, key interface{}, val interface{}) Context {
-	return context.WithValue(parent, key, val)
-}
diff --git a/build/_vendor/src/golang.org/x/net/context/pre_go17.go b/build/_vendor/src/golang.org/x/net/context/pre_go17.go
deleted file mode 100644
index 5a30acabd0..0000000000
--- a/build/_vendor/src/golang.org/x/net/context/pre_go17.go
+++ /dev/null
@@ -1,300 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build !go1.7
-
-package context
-
-import (
-	"errors"
-	"fmt"
-	"sync"
-	"time"
-)
-
-// An emptyCtx is never canceled, has no values, and has no deadline.  It is not
-// struct{}, since vars of this type must have distinct addresses.
-type emptyCtx int
-
-func (*emptyCtx) Deadline() (deadline time.Time, ok bool) {
-	return
-}
-
-func (*emptyCtx) Done() <-chan struct{} {
-	return nil
-}
-
-func (*emptyCtx) Err() error {
-	return nil
-}
-
-func (*emptyCtx) Value(key interface{}) interface{} {
-	return nil
-}
-
-func (e *emptyCtx) String() string {
-	switch e {
-	case background:
-		return "context.Background"
-	case todo:
-		return "context.TODO"
-	}
-	return "unknown empty Context"
-}
-
-var (
-	background = new(emptyCtx)
-	todo       = new(emptyCtx)
-)
-
-// Canceled is the error returned by Context.Err when the context is canceled.
-var Canceled = errors.New("context canceled")
-
-// DeadlineExceeded is the error returned by Context.Err when the context's
-// deadline passes.
-var DeadlineExceeded = errors.New("context deadline exceeded")
-
-// WithCancel returns a copy of parent with a new Done channel. The returned
-// context's Done channel is closed when the returned cancel function is called
-// or when the parent context's Done channel is closed, whichever happens first.
-//
-// Canceling this context releases resources associated with it, so code should
-// call cancel as soon as the operations running in this Context complete.
-func WithCancel(parent Context) (ctx Context, cancel CancelFunc) {
-	c := newCancelCtx(parent)
-	propagateCancel(parent, c)
-	return c, func() { c.cancel(true, Canceled) }
-}
-
-// newCancelCtx returns an initialized cancelCtx.
-func newCancelCtx(parent Context) *cancelCtx {
-	return &cancelCtx{
-		Context: parent,
-		done:    make(chan struct{}),
-	}
-}
-
-// propagateCancel arranges for child to be canceled when parent is.
-func propagateCancel(parent Context, child canceler) {
-	if parent.Done() == nil {
-		return // parent is never canceled
-	}
-	if p, ok := parentCancelCtx(parent); ok {
-		p.mu.Lock()
-		if p.err != nil {
-			// parent has already been canceled
-			child.cancel(false, p.err)
-		} else {
-			if p.children == nil {
-				p.children = make(map[canceler]bool)
-			}
-			p.children[child] = true
-		}
-		p.mu.Unlock()
-	} else {
-		go func() {
-			select {
-			case <-parent.Done():
-				child.cancel(false, parent.Err())
-			case <-child.Done():
-			}
-		}()
-	}
-}
-
-// parentCancelCtx follows a chain of parent references until it finds a
-// *cancelCtx.  This function understands how each of the concrete types in this
-// package represents its parent.
-func parentCancelCtx(parent Context) (*cancelCtx, bool) {
-	for {
-		switch c := parent.(type) {
-		case *cancelCtx:
-			return c, true
-		case *timerCtx:
-			return c.cancelCtx, true
-		case *valueCtx:
-			parent = c.Context
-		default:
-			return nil, false
-		}
-	}
-}
-
-// removeChild removes a context from its parent.
-func removeChild(parent Context, child canceler) {
-	p, ok := parentCancelCtx(parent)
-	if !ok {
-		return
-	}
-	p.mu.Lock()
-	if p.children != nil {
-		delete(p.children, child)
-	}
-	p.mu.Unlock()
-}
-
-// A canceler is a context type that can be canceled directly.  The
-// implementations are *cancelCtx and *timerCtx.
-type canceler interface {
-	cancel(removeFromParent bool, err error)
-	Done() <-chan struct{}
-}
-
-// A cancelCtx can be canceled.  When canceled, it also cancels any children
-// that implement canceler.
-type cancelCtx struct {
-	Context
-
-	done chan struct{} // closed by the first cancel call.
-
-	mu       sync.Mutex
-	children map[canceler]bool // set to nil by the first cancel call
-	err      error             // set to non-nil by the first cancel call
-}
-
-func (c *cancelCtx) Done() <-chan struct{} {
-	return c.done
-}
-
-func (c *cancelCtx) Err() error {
-	c.mu.Lock()
-	defer c.mu.Unlock()
-	return c.err
-}
-
-func (c *cancelCtx) String() string {
-	return fmt.Sprintf("%v.WithCancel", c.Context)
-}
-
-// cancel closes c.done, cancels each of c's children, and, if
-// removeFromParent is true, removes c from its parent's children.
-func (c *cancelCtx) cancel(removeFromParent bool, err error) {
-	if err == nil {
-		panic("context: internal error: missing cancel error")
-	}
-	c.mu.Lock()
-	if c.err != nil {
-		c.mu.Unlock()
-		return // already canceled
-	}
-	c.err = err
-	close(c.done)
-	for child := range c.children {
-		// NOTE: acquiring the child's lock while holding parent's lock.
-		child.cancel(false, err)
-	}
-	c.children = nil
-	c.mu.Unlock()
-
-	if removeFromParent {
-		removeChild(c.Context, c)
-	}
-}
-
-// WithDeadline returns a copy of the parent context with the deadline adjusted
-// to be no later than d.  If the parent's deadline is already earlier than d,
-// WithDeadline(parent, d) is semantically equivalent to parent.  The returned
-// context's Done channel is closed when the deadline expires, when the returned
-// cancel function is called, or when the parent context's Done channel is
-// closed, whichever happens first.
-//
-// Canceling this context releases resources associated with it, so code should
-// call cancel as soon as the operations running in this Context complete.
-func WithDeadline(parent Context, deadline time.Time) (Context, CancelFunc) {
-	if cur, ok := parent.Deadline(); ok && cur.Before(deadline) {
-		// The current deadline is already sooner than the new one.
-		return WithCancel(parent)
-	}
-	c := &timerCtx{
-		cancelCtx: newCancelCtx(parent),
-		deadline:  deadline,
-	}
-	propagateCancel(parent, c)
-	d := deadline.Sub(time.Now())
-	if d <= 0 {
-		c.cancel(true, DeadlineExceeded) // deadline has already passed
-		return c, func() { c.cancel(true, Canceled) }
-	}
-	c.mu.Lock()
-	defer c.mu.Unlock()
-	if c.err == nil {
-		c.timer = time.AfterFunc(d, func() {
-			c.cancel(true, DeadlineExceeded)
-		})
-	}
-	return c, func() { c.cancel(true, Canceled) }
-}
-
-// A timerCtx carries a timer and a deadline.  It embeds a cancelCtx to
-// implement Done and Err.  It implements cancel by stopping its timer then
-// delegating to cancelCtx.cancel.
-type timerCtx struct {
-	*cancelCtx
-	timer *time.Timer // Under cancelCtx.mu.
-
-	deadline time.Time
-}
-
-func (c *timerCtx) Deadline() (deadline time.Time, ok bool) {
-	return c.deadline, true
-}
-
-func (c *timerCtx) String() string {
-	return fmt.Sprintf("%v.WithDeadline(%s [%s])", c.cancelCtx.Context, c.deadline, c.deadline.Sub(time.Now()))
-}
-
-func (c *timerCtx) cancel(removeFromParent bool, err error) {
-	c.cancelCtx.cancel(false, err)
-	if removeFromParent {
-		// Remove this timerCtx from its parent cancelCtx's children.
-		removeChild(c.cancelCtx.Context, c)
-	}
-	c.mu.Lock()
-	if c.timer != nil {
-		c.timer.Stop()
-		c.timer = nil
-	}
-	c.mu.Unlock()
-}
-
-// WithTimeout returns WithDeadline(parent, time.Now().Add(timeout)).
-//
-// Canceling this context releases resources associated with it, so code should
-// call cancel as soon as the operations running in this Context complete:
-//
-// 	func slowOperationWithTimeout(ctx context.Context) (Result, error) {
-// 		ctx, cancel := context.WithTimeout(ctx, 100*time.Millisecond)
-// 		defer cancel()  // releases resources if slowOperation completes before timeout elapses
-// 		return slowOperation(ctx)
-// 	}
-func WithTimeout(parent Context, timeout time.Duration) (Context, CancelFunc) {
-	return WithDeadline(parent, time.Now().Add(timeout))
-}
-
-// WithValue returns a copy of parent in which the value associated with key is
-// val.
-//
-// Use context Values only for request-scoped data that transits processes and
-// APIs, not for passing optional parameters to functions.
-func WithValue(parent Context, key interface{}, val interface{}) Context {
-	return &valueCtx{parent, key, val}
-}
-
-// A valueCtx carries a key-value pair.  It implements Value for that key and
-// delegates all other calls to the embedded Context.
-type valueCtx struct {
-	Context
-	key, val interface{}
-}
-
-func (c *valueCtx) String() string {
-	return fmt.Sprintf("%v.WithValue(%#v, %#v)", c.Context, c.key, c.val)
-}
-
-func (c *valueCtx) Value(key interface{}) interface{} {
-	if c.key == key {
-		return c.val
-	}
-	return c.Context.Value(key)
-}
diff --git a/build/ci-notes.md b/build/ci-notes.md
index 5546aea30a..26d2f5652d 100644
--- a/build/ci-notes.md
+++ b/build/ci-notes.md
@@ -1,18 +1,3 @@
-# Vendored Dependencies
-
-Dependencies are almost all vendored in at the standard Go `/vendor` path. This allows
-people to build go-ubiq using the standard toolchain without any particular package
-manager. It also plays nicely with `go get`, not requiring external code to be relied on.
-
-The one single dependent package missing from `vendor` is `golang.org/x/net/context`. As
-this is a package exposed via public library APIs, it must not be vendored as dependent
-code woulnd't be able to instantiate.
-
-To allow reproducible builds of go-ubiq nonetheless that don't need network access
-during build time to fetch `golang.org/x/net/context`, a version was copied into our repo
-at the very specific `/build/_vendor` path, which is added automatically by all CI build
-scripts and the makefile too.
-
 # Debian Packaging
 
 Tagged releases and develop branch commits are available as installable Debian packages
diff --git a/contracts/chequebook/cheque.go b/contracts/chequebook/cheque.go
index 42ec391ca0..f0bcc52afd 100644
--- a/contracts/chequebook/cheque.go
+++ b/contracts/chequebook/cheque.go
@@ -26,6 +26,7 @@ package chequebook
 
 import (
 	"bytes"
+	"context"
 	"crypto/ecdsa"
 	"encoding/json"
 	"fmt"
@@ -43,7 +44,6 @@ import (
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
 	"github.com/ubiq/go-ubiq/swarm/services/swap/swap"
-	"golang.org/x/net/context"
 )
 
 // TODO(zelig): watch peer solvency and notify of bouncing cheques
diff --git a/contracts/release/release.go b/contracts/release/release.go
index 835c1d5343..49d0236661 100644
--- a/contracts/release/release.go
+++ b/contracts/release/release.go
@@ -20,6 +20,7 @@ package release
 //go:generate abigen --sol ./contract.sol --pkg release --out ./contract.go
 
 import (
+	"context"
 	"fmt"
 	"strings"
 	"time"
@@ -34,7 +35,6 @@ import (
 	"github.com/ubiq/go-ubiq/node"
 	"github.com/ubiq/go-ubiq/p2p"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 // Interval to check for new releases
@@ -117,46 +117,48 @@ func (r *ReleaseService) checker() {
 
 	for {
 		select {
-		// If the time arrived, check for a new release
 		case <-timer.C:
 			// Rechedule the timer before continuing
 			timer.Reset(releaseRecheckInterval)
-
-			// Retrieve the current version, and handle missing contracts gracefully
-			ctx, _ := context.WithTimeout(context.Background(), time.Second*5)
-			opts := &bind.CallOpts{Context: ctx}
-			version, err := r.oracle.CurrentVersion(opts)
-			if err != nil {
-				if err == bind.ErrNoCode {
-					glog.V(logger.Debug).Infof("Release oracle not found at %x", r.config.Oracle)
-					continue
-				}
-				glog.V(logger.Error).Infof("Failed to retrieve current release: %v", err)
-				continue
-			}
-			// Version was successfully retrieved, notify if newer than ours
-			if version.Major > r.config.Major ||
-				(version.Major == r.config.Major && version.Minor > r.config.Minor) ||
-				(version.Major == r.config.Major && version.Minor == r.config.Minor && version.Patch > r.config.Patch) {
-
-				warning := fmt.Sprintf("Client v%d.%d.%d-%x seems older than the latest upstream release v%d.%d.%d-%x",
-					r.config.Major, r.config.Minor, r.config.Patch, r.config.Commit[:4], version.Major, version.Minor, version.Patch, version.Commit[:4])
-				howtofix := fmt.Sprintf("Please check https://github.com/ubiq/go-ubiq/releases for new releases")
-				separator := strings.Repeat("-", len(warning))
-
-				glog.V(logger.Warn).Info(separator)
-				glog.V(logger.Warn).Info(warning)
-				glog.V(logger.Warn).Info(howtofix)
-				glog.V(logger.Warn).Info(separator)
-			} else {
-				glog.V(logger.Debug).Infof("Client v%d.%d.%d-%x seems up to date with upstream v%d.%d.%d-%x",
-					r.config.Major, r.config.Minor, r.config.Patch, r.config.Commit[:4], version.Major, version.Minor, version.Patch, version.Commit[:4])
-			}
-
-		// If termination was requested, return
+			r.checkVersion()
 		case errc := <-r.quit:
 			errc <- nil
 			return
 		}
 	}
 }
+
+func (r *ReleaseService) checkVersion() {
+	// Retrieve the current version, and handle missing contracts gracefully
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
+	opts := &bind.CallOpts{Context: ctx}
+	defer cancel()
+
+	version, err := r.oracle.CurrentVersion(opts)
+	if err != nil {
+		if err == bind.ErrNoCode {
+			glog.V(logger.Debug).Infof("Release oracle not found at %x", r.config.Oracle)
+		} else {
+			glog.V(logger.Error).Infof("Failed to retrieve current release: %v", err)
+		}
+		return
+	}
+	// Version was successfully retrieved, notify if newer than ours
+	if version.Major > r.config.Major ||
+		(version.Major == r.config.Major && version.Minor > r.config.Minor) ||
+		(version.Major == r.config.Major && version.Minor == r.config.Minor && version.Patch > r.config.Patch) {
+
+		warning := fmt.Sprintf("Client v%d.%d.%d-%x seems older than the latest upstream release v%d.%d.%d-%x",
+			r.config.Major, r.config.Minor, r.config.Patch, r.config.Commit[:4], version.Major, version.Minor, version.Patch, version.Commit[:4])
+		howtofix := fmt.Sprintf("Please check https://github.com/ethereum/go-ethereum/releases for new releases")
+		separator := strings.Repeat("-", len(warning))
+
+		glog.V(logger.Warn).Info(separator)
+		glog.V(logger.Warn).Info(warning)
+		glog.V(logger.Warn).Info(howtofix)
+		glog.V(logger.Warn).Info(separator)
+	} else {
+		glog.V(logger.Debug).Infof("Client v%d.%d.%d-%x seems up to date with upstream v%d.%d.%d-%x",
+			r.config.Major, r.config.Minor, r.config.Patch, r.config.Commit[:4], version.Major, version.Minor, version.Patch, version.Commit[:4])
+	}
+}
diff --git a/eth/api.go b/eth/api.go
index b239599a2f..2f7eaf5436 100644
--- a/eth/api.go
+++ b/eth/api.go
@@ -19,6 +19,7 @@ package eth
 import (
 	"bytes"
 	"compress/gzip"
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -43,7 +44,6 @@ import (
 	"github.com/ubiq/go-ubiq/params"
 	"github.com/ubiq/go-ubiq/rlp"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 const defaultTraceTimeout = 5 * time.Second
diff --git a/eth/api_backend.go b/eth/api_backend.go
index 89e9ce3019..005d8ea387 100644
--- a/eth/api_backend.go
+++ b/eth/api_backend.go
@@ -17,6 +17,7 @@
 package eth
 
 import (
+	"context"
 	"math/big"
 
 	"github.com/ubiq/go-ubiq/accounts"
@@ -32,7 +33,6 @@ import (
 	"github.com/ubiq/go-ubiq/internal/ethapi"
 	"github.com/ubiq/go-ubiq/params"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 // EthApiBackend implements ethapi.Backend for full nodes
diff --git a/eth/bind.go b/eth/bind.go
index 52b4b9f86a..4e1668f413 100644
--- a/eth/bind.go
+++ b/eth/bind.go
@@ -17,6 +17,7 @@
 package eth
 
 import (
+	"context"
 	"math/big"
 
 	"github.com/ubiq/go-ubiq"
@@ -26,7 +27,6 @@ import (
 	"github.com/ubiq/go-ubiq/internal/ethapi"
 	"github.com/ubiq/go-ubiq/rlp"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 // ContractBackend implements bind.ContractBackend with direct calls to Ethereum
diff --git a/eth/downloader/api.go b/eth/downloader/api.go
index a198ea60d9..f5d83297a6 100644
--- a/eth/downloader/api.go
+++ b/eth/downloader/api.go
@@ -17,12 +17,12 @@
 package downloader
 
 import (
+	"context"
 	"sync"
 
 	ethereum "github.com/ubiq/go-ubiq"
 	"github.com/ubiq/go-ubiq/event"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 // PublicDownloaderAPI provides an API which gives information about the current synchronisation status.
diff --git a/eth/filters/api.go b/eth/filters/api.go
index 7d9eee6113..c9e495999c 100644
--- a/eth/filters/api.go
+++ b/eth/filters/api.go
@@ -17,6 +17,7 @@
 package filters
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -24,8 +25,6 @@ import (
 	"sync"
 	"time"
 
-	"golang.org/x/net/context"
-
 	"github.com/ubiq/go-ubiq/common"
 	"github.com/ubiq/go-ubiq/common/hexutil"
 	"github.com/ubiq/go-ubiq/core/types"
diff --git a/eth/filters/filter.go b/eth/filters/filter.go
index 6d49b68490..3ee10578f2 100644
--- a/eth/filters/filter.go
+++ b/eth/filters/filter.go
@@ -17,6 +17,7 @@
 package filters
 
 import (
+	"context"
 	"math"
 	"time"
 	"math/big"
@@ -27,7 +28,6 @@ import (
 	"github.com/ubiq/go-ubiq/ethdb"
 	"github.com/ubiq/go-ubiq/event"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 type Backend interface {
diff --git a/eth/filters/filter_system.go b/eth/filters/filter_system.go
index 5a9ac4a975..413bc91a3d 100644
--- a/eth/filters/filter_system.go
+++ b/eth/filters/filter_system.go
@@ -19,6 +19,7 @@
 package filters
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"sync"
@@ -29,7 +30,6 @@ import (
 	"github.com/ubiq/go-ubiq/core/types"
 	"github.com/ubiq/go-ubiq/event"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 // Type determines the kind of filter and is used to put the filter in to
@@ -372,7 +372,8 @@ func (es *EventSystem) lightFilterNewHead(newHeader *types.Header, callBack func
 func (es *EventSystem) lightFilterLogs(header *types.Header, addresses []common.Address, topics [][]common.Hash, remove bool) []*types.Log {
 	if bloomFilter(header.Bloom, addresses, topics) {
 		// Get the logs of the block
-		ctx, _ := context.WithTimeout(context.Background(), time.Second*5)
+		ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
+		defer cancel()
 		receipts, err := es.backend.GetReceipts(ctx, header.Hash())
 		if err != nil {
 			return nil
diff --git a/eth/filters/filter_system_test.go b/eth/filters/filter_system_test.go
index fd1460434b..17f0e11729 100644
--- a/eth/filters/filter_system_test.go
+++ b/eth/filters/filter_system_test.go
@@ -17,13 +17,12 @@
 package filters
 
 import (
+	"context"
 	"math/big"
 	"reflect"
 	"testing"
 	"time"
 
-	"golang.org/x/net/context"
-
 	"github.com/ubiq/go-ubiq/common"
 	"github.com/ubiq/go-ubiq/core"
 	"github.com/ubiq/go-ubiq/core/types"
diff --git a/eth/filters/filter_test.go b/eth/filters/filter_test.go
index 478a43e060..4cbb0299b3 100644
--- a/eth/filters/filter_test.go
+++ b/eth/filters/filter_test.go
@@ -17,13 +17,12 @@
 package filters
 
 import (
+	"context"
 	"io/ioutil"
 	"math/big"
 	"os"
 	"testing"
 
-	"golang.org/x/net/context"
-
 	"github.com/ubiq/go-ubiq/common"
 	"github.com/ubiq/go-ubiq/core"
 	"github.com/ubiq/go-ubiq/core/types"
diff --git a/eth/gasprice/lightprice.go b/eth/gasprice/lightprice.go
index 32ba0e8ee0..091d3f98a6 100644
--- a/eth/gasprice/lightprice.go
+++ b/eth/gasprice/lightprice.go
@@ -17,6 +17,7 @@
 package gasprice
 
 import (
+	"context"
 	"math/big"
 	"sort"
 	"sync"
@@ -24,7 +25,6 @@ import (
 	"github.com/ubiq/go-ubiq/common"
 	"github.com/ubiq/go-ubiq/internal/ethapi"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 const (
diff --git a/ethclient/ethclient.go b/ethclient/ethclient.go
index 06db3f458f..37da24bcc2 100644
--- a/ethclient/ethclient.go
+++ b/ethclient/ethclient.go
@@ -18,6 +18,7 @@
 package ethclient
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"math/big"
@@ -28,7 +29,6 @@ import (
 	"github.com/ubiq/go-ubiq/core/types"
 	"github.com/ubiq/go-ubiq/rlp"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 // Client defines typed wrappers for the Ethereum RPC API.
diff --git a/event/subscription.go b/event/subscription.go
index 3318319fdc..313a04976b 100644
--- a/event/subscription.go
+++ b/event/subscription.go
@@ -17,11 +17,11 @@
 package event
 
 import (
+	"context"
 	"sync"
 	"time"
 
 	"github.com/ubiq/go-ubiq/common/mclock"
-	"golang.org/x/net/context"
 )
 
 // Subscription represents a stream of events. The carrier of the events is typically a
diff --git a/event/subscription_test.go b/event/subscription_test.go
index a4fe30298c..aa6d98984d 100644
--- a/event/subscription_test.go
+++ b/event/subscription_test.go
@@ -17,11 +17,10 @@
 package event
 
 import (
+	"context"
 	"errors"
 	"testing"
 	"time"
-
-	"golang.org/x/net/context"
 )
 
 var errInts = errors.New("error in subscribeInts")
diff --git a/interfaces.go b/interfaces.go
index fef95f60af..4ef6c16c49 100644
--- a/interfaces.go
+++ b/interfaces.go
@@ -18,12 +18,12 @@
 package ethereum
 
 import (
+	"context"
 	"errors"
 	"math/big"
 
 	"github.com/ubiq/go-ubiq/common"
 	"github.com/ubiq/go-ubiq/core/types"
-	"golang.org/x/net/context"
 )
 
 // NotFound is returned by API methods if the requested item does not exist.
diff --git a/internal/build/util.go b/internal/build/util.go
index 1523a067bc..4df7b91381 100644
--- a/internal/build/util.go
+++ b/internal/build/util.go
@@ -52,19 +52,10 @@ func MustRunCommand(cmd string, args ...string) {
 // GOPATH returns the value that the GOPATH environment
 // variable should be set to.
 func GOPATH() string {
-	path := filepath.SplitList(os.Getenv("GOPATH"))
-	if len(path) == 0 {
+	if os.Getenv("GOPATH") == "" {
 		log.Fatal("GOPATH is not set")
 	}
-	// Ensure that our internal vendor folder is on GOPATH
-	vendor, _ := filepath.Abs(filepath.Join("build", "_vendor"))
-	for _, dir := range path {
-		if dir == vendor {
-			return strings.Join(path, string(filepath.ListSeparator))
-		}
-	}
-	newpath := append(path[:1], append([]string{vendor}, path[1:]...)...)
-	return strings.Join(newpath, string(filepath.ListSeparator))
+	return os.Getenv("GOPATH")
 }
 
 // VERSION returns the content of the VERSION file.
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 220be13d78..cd2486cd25 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -17,6 +17,7 @@
 package ethapi
 
 import (
+	"context"
 	"encoding/hex"
 	"errors"
 	"fmt"
@@ -41,7 +42,6 @@ import (
 	"github.com/ubiq/go-ubiq/p2p"
 	"github.com/ubiq/go-ubiq/rlp"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 const defaultGas = 90000
diff --git a/internal/ethapi/backend.go b/internal/ethapi/backend.go
index eb0ca2a1f9..9e7be80836 100644
--- a/internal/ethapi/backend.go
+++ b/internal/ethapi/backend.go
@@ -18,6 +18,7 @@
 package ethapi
 
 import (
+	"context"
 	"math/big"
 
 	"github.com/ubiq/go-ubiq/accounts"
@@ -30,7 +31,6 @@ import (
 	"github.com/ubiq/go-ubiq/event"
 	"github.com/ubiq/go-ubiq/params"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 // Backend interface provides the common API services (that are provided by
diff --git a/les/api_backend.go b/les/api_backend.go
index 85bf0f6894..5988e9842e 100644
--- a/les/api_backend.go
+++ b/les/api_backend.go
@@ -17,6 +17,7 @@
 package les
 
 import (
+	"context"
 	"math/big"
 
 	"github.com/ubiq/go-ubiq/accounts"
@@ -32,7 +33,6 @@ import (
 	"github.com/ubiq/go-ubiq/light"
 	"github.com/ubiq/go-ubiq/params"
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 type LesApiBackend struct {
diff --git a/les/odr.go b/les/odr.go
index 041cc9aee1..5014a623f1 100644
--- a/les/odr.go
+++ b/les/odr.go
@@ -17,6 +17,7 @@
 package les
 
 import (
+	"context"
 	"crypto/rand"
 	"encoding/binary"
 	"sync"
@@ -27,7 +28,6 @@ import (
 	"github.com/ubiq/go-ubiq/light"
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
-	"golang.org/x/net/context"
 )
 
 var (
diff --git a/les/odr_test.go b/les/odr_test.go
index 232ee39454..41a15101b8 100644
--- a/les/odr_test.go
+++ b/les/odr_test.go
@@ -18,6 +18,7 @@ package les
 
 import (
 	"bytes"
+	"context"
 	"math/big"
 	"testing"
 	"time"
@@ -31,7 +32,6 @@ import (
 	"github.com/ubiq/go-ubiq/light"
 	"github.com/ubiq/go-ubiq/params"
 	"github.com/ubiq/go-ubiq/rlp"
-	"golang.org/x/net/context"
 )
 
 type odrTestFn func(ctx context.Context, db ethdb.Database, config *params.ChainConfig, bc *core.BlockChain, lc *light.LightChain, bhash common.Hash) []byte
@@ -177,7 +177,8 @@ func testOdr(t *testing.T, protocol int, expFail uint64, fn odrTestFn) {
 		for i := uint64(0); i <= pm.blockchain.CurrentHeader().Number.Uint64(); i++ {
 			bhash := core.GetCanonicalHash(db, i)
 			b1 := fn(light.NoOdr, db, pm.chainConfig, pm.blockchain.(*core.BlockChain), nil, bhash)
-			ctx, _ := context.WithTimeout(context.Background(), 200*time.Millisecond)
+			ctx, cancel := context.WithTimeout(context.Background(), 200*time.Millisecond)
+			defer cancel()
 			b2 := fn(ctx, ldb, lpm.chainConfig, nil, lpm.blockchain.(*light.LightChain), bhash)
 			eq := bytes.Equal(b1, b2)
 			exp := i < expFail
diff --git a/les/request_test.go b/les/request_test.go
index 0960bacc47..75d1da2168 100644
--- a/les/request_test.go
+++ b/les/request_test.go
@@ -17,6 +17,7 @@
 package les
 
 import (
+	"context"
 	"testing"
 	"time"
 
@@ -25,7 +26,6 @@ import (
 	"github.com/ubiq/go-ubiq/crypto"
 	"github.com/ubiq/go-ubiq/ethdb"
 	"github.com/ubiq/go-ubiq/light"
-	"golang.org/x/net/context"
 )
 
 var testBankSecureTrieKey = secAddr(testBankAddress)
@@ -88,7 +88,9 @@ func testAccess(t *testing.T, protocol int, fn accessTestFn) {
 		for i := uint64(0); i <= pm.blockchain.CurrentHeader().Number.Uint64(); i++ {
 			bhash := core.GetCanonicalHash(db, i)
 			if req := fn(ldb, bhash, i); req != nil {
-				ctx, _ := context.WithTimeout(context.Background(), 200*time.Millisecond)
+				ctx, cancel := context.WithTimeout(context.Background(), 200*time.Millisecond)
+				defer cancel()
+
 				err := odr.Retrieve(ctx, req)
 				got := err == nil
 				exp := i < expFail
diff --git a/les/sync.go b/les/sync.go
index 5c09de8c1d..a4bbb150f7 100644
--- a/les/sync.go
+++ b/les/sync.go
@@ -17,12 +17,12 @@
 package les
 
 import (
+	"context"
 	"time"
 
 	"github.com/ubiq/go-ubiq/core"
 	"github.com/ubiq/go-ubiq/eth/downloader"
 	"github.com/ubiq/go-ubiq/light"
-	"golang.org/x/net/context"
 )
 
 const (
@@ -77,8 +77,8 @@ func (pm *ProtocolManager) synchronise(peer *peer) {
 		return
 	}
 
-	ctx, _ := context.WithTimeout(context.Background(), time.Second*5)
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
+	defer cancel()
 	pm.blockchain.(*light.LightChain).SyncCht(ctx)
-
 	pm.downloader.Synchronise(peer.id, peer.Head(), peer.Td(), downloader.LightSync)
 }
diff --git a/light/lightchain.go b/light/lightchain.go
index 7e035d5e83..299e2d5975 100644
--- a/light/lightchain.go
+++ b/light/lightchain.go
@@ -17,6 +17,7 @@
 package light
 
 import (
+	"context"
 	"math/big"
 	"sync"
 	"sync/atomic"
@@ -33,7 +34,6 @@ import (
 	"github.com/ubiq/go-ubiq/params"
 	"github.com/ubiq/go-ubiq/pow"
 	"github.com/ubiq/go-ubiq/rlp"
-	"golang.org/x/net/context"
 )
 
 var (
diff --git a/light/lightchain_test.go b/light/lightchain_test.go
index aa52385af2..053a92f75f 100644
--- a/light/lightchain_test.go
+++ b/light/lightchain_test.go
@@ -17,6 +17,7 @@
 package light
 
 import (
+	"context"
 	"fmt"
 	"math/big"
 	"runtime"
@@ -31,7 +32,6 @@ import (
 	"github.com/ubiq/go-ubiq/params"
 	"github.com/ubiq/go-ubiq/pow"
 	"github.com/hashicorp/golang-lru"
-	"golang.org/x/net/context"
 )
 
 // So we can deterministically seed different blockchains
diff --git a/light/odr.go b/light/odr.go
index 197ed152cd..6d86c80917 100644
--- a/light/odr.go
+++ b/light/odr.go
@@ -19,6 +19,7 @@
 package light
 
 import (
+	"context"
 	"math/big"
 
 	"github.com/ubiq/go-ubiq/common"
@@ -27,7 +28,6 @@ import (
 	"github.com/ubiq/go-ubiq/crypto"
 	"github.com/ubiq/go-ubiq/ethdb"
 	"github.com/ubiq/go-ubiq/rlp"
-	"golang.org/x/net/context"
 )
 
 // NoOdr is the default context passed to an ODR capable function when the ODR
diff --git a/light/odr_test.go b/light/odr_test.go
index 6b2b993635..18c31c1a08 100644
--- a/light/odr_test.go
+++ b/light/odr_test.go
@@ -18,6 +18,7 @@ package light
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"math/big"
 	"testing"
@@ -34,7 +35,6 @@ import (
 	"github.com/ubiq/go-ubiq/params"
 	"github.com/ubiq/go-ubiq/rlp"
 	"github.com/ubiq/go-ubiq/trie"
-	"golang.org/x/net/context"
 )
 
 var (
@@ -273,7 +273,8 @@ func testChainOdr(t *testing.T, protocol int, expFail uint64, fn odrTestFn) {
 		for i := uint64(0); i <= blockchain.CurrentHeader().Number.Uint64(); i++ {
 			bhash := core.GetCanonicalHash(sdb, i)
 			b1 := fn(NoOdr, sdb, blockchain, nil, bhash)
-			ctx, _ := context.WithTimeout(context.Background(), 200*time.Millisecond)
+			ctx, cancel := context.WithTimeout(context.Background(), 200*time.Millisecond)
+			defer cancel()
 			b2 := fn(ctx, ldb, nil, lightchain, bhash)
 			eq := bytes.Equal(b1, b2)
 			exp := i < expFail
diff --git a/light/odr_util.go b/light/odr_util.go
index 1cb3605360..3131025912 100644
--- a/light/odr_util.go
+++ b/light/odr_util.go
@@ -18,6 +18,7 @@ package light
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"math/big"
 
@@ -29,7 +30,6 @@ import (
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
 	"github.com/ubiq/go-ubiq/rlp"
-	"golang.org/x/net/context"
 )
 
 var sha3_nil = crypto.Keccak256Hash(nil)
diff --git a/light/state.go b/light/state.go
index cb51c1ac3d..a7e2a45ad6 100644
--- a/light/state.go
+++ b/light/state.go
@@ -17,13 +17,13 @@
 package light
 
 import (
+	"context"
 	"math/big"
 
 	"github.com/ubiq/go-ubiq/common"
 	"github.com/ubiq/go-ubiq/crypto"
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
-	"golang.org/x/net/context"
 )
 
 // LightState is a memory representation of a state.
diff --git a/light/state_object.go b/light/state_object.go
index 17044df479..eb9d12b68e 100644
--- a/light/state_object.go
+++ b/light/state_object.go
@@ -18,6 +18,7 @@ package light
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"math/big"
 
@@ -26,7 +27,6 @@ import (
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
 	"github.com/ubiq/go-ubiq/rlp"
-	"golang.org/x/net/context"
 )
 
 var emptyCodeHash = crypto.Keccak256(nil)
diff --git a/light/state_test.go b/light/state_test.go
index 7b9ce4f618..be2f2cafea 100644
--- a/light/state_test.go
+++ b/light/state_test.go
@@ -18,6 +18,7 @@ package light
 
 import (
 	"bytes"
+	"context"
 	"math/big"
 	"testing"
 
@@ -26,7 +27,6 @@ import (
 	"github.com/ubiq/go-ubiq/core/state"
 	"github.com/ubiq/go-ubiq/core/types"
 	"github.com/ubiq/go-ubiq/ethdb"
-	"golang.org/x/net/context"
 )
 
 func makeTestState() (common.Hash, ethdb.Database) {
diff --git a/light/trie.go b/light/trie.go
index 81a68a2f00..01ac30d223 100644
--- a/light/trie.go
+++ b/light/trie.go
@@ -17,9 +17,9 @@
 package light
 
 import (
+	"context"
 	"github.com/ubiq/go-ubiq/ethdb"
 	"github.com/ubiq/go-ubiq/trie"
-	"golang.org/x/net/context"
 )
 
 // LightTrie is an ODR-capable wrapper around trie.SecureTrie
diff --git a/light/txpool.go b/light/txpool.go
index 8dc67bd5bc..90ad99281a 100644
--- a/light/txpool.go
+++ b/light/txpool.go
@@ -17,6 +17,7 @@
 package light
 
 import (
+	"context"
 	"fmt"
 	"sync"
 	"time"
@@ -30,7 +31,6 @@ import (
 	"github.com/ubiq/go-ubiq/logger/glog"
 	"github.com/ubiq/go-ubiq/params"
 	"github.com/ubiq/go-ubiq/rlp"
-	"golang.org/x/net/context"
 )
 
 // txPermanent is the number of mined blocks after a mined transaction is
@@ -207,13 +207,13 @@ func (pool *TxPool) rollbackTxs(hash common.Hash, txc txStateChanges) {
 	}
 }
 
-// setNewHead sets a new head header, processing (and rolling back if necessary)
+// reorgOnNewHead sets a new head header, processing (and rolling back if necessary)
 // the blocks since the last known head and returns a txStateChanges map containing
 // the recently mined and rolled back transaction hashes. If an error (context
 // timeout) occurs during checking new blocks, it leaves the locally known head
 // at the latest checked block and still returns a valid txStateChanges, making it
 // possible to continue checking the missing blocks at the next chain head event
-func (pool *TxPool) setNewHead(ctx context.Context, newHeader *types.Header) (txStateChanges, error) {
+func (pool *TxPool) reorgOnNewHead(ctx context.Context, newHeader *types.Header) (txStateChanges, error) {
 	txc := make(txStateChanges)
 	oldh := pool.chain.GetHeaderByHash(pool.head)
 	newh := newHeader
@@ -253,15 +253,17 @@ func (pool *TxPool) setNewHead(ctx context.Context, newHeader *types.Header) (tx
 	// clear old mined tx entries of old blocks
 	if idx := newHeader.Number.Uint64(); idx > pool.clearIdx+txPermanent {
 		idx2 := idx - txPermanent
-		for i := pool.clearIdx; i < idx2; i++ {
-			hash := core.GetCanonicalHash(pool.chainDb, i)
-			if list, ok := pool.mined[hash]; ok {
-				hashes := make([]common.Hash, len(list))
-				for i, tx := range list {
-					hashes[i] = tx.Hash()
+		if len(pool.mined) > 0 {
+			for i := pool.clearIdx; i < idx2; i++ {
+				hash := core.GetCanonicalHash(pool.chainDb, i)
+				if list, ok := pool.mined[hash]; ok {
+					hashes := make([]common.Hash, len(list))
+					for i, tx := range list {
+						hashes[i] = tx.Hash()
+					}
+					pool.relay.Discard(hashes)
+					delete(pool.mined, hash)
 				}
-				pool.relay.Discard(hashes)
-				delete(pool.mined, hash)
 			}
 		}
 		pool.clearIdx = idx2
@@ -280,19 +282,28 @@ func (pool *TxPool) eventLoop() {
 	for ev := range pool.events.Chan() {
 		switch ev.Data.(type) {
 		case core.ChainHeadEvent:
-			pool.mu.Lock()
-			ctx, _ := context.WithTimeout(context.Background(), blockCheckTimeout)
-			head := pool.chain.CurrentHeader()
-			txc, _ := pool.setNewHead(ctx, head)
-			m, r := txc.getLists()
-			pool.relay.NewHead(pool.head, m, r)
-			pool.homestead = pool.config.IsHomestead(head.Number)
-			pool.signer = types.MakeSigner(pool.config, head.Number)
-			pool.mu.Unlock()
+			pool.setNewHead(ev.Data.(core.ChainHeadEvent).Block.Header())
+			// hack in order to avoid hogging the lock; this part will
+			// be replaced by a subsequent PR.
+			time.Sleep(time.Millisecond)
 		}
 	}
 }
 
+func (pool *TxPool) setNewHead(head *types.Header) {
+	pool.mu.Lock()
+	defer pool.mu.Unlock()
+
+	ctx, cancel := context.WithTimeout(context.Background(), blockCheckTimeout)
+	defer cancel()
+
+	txc, _ := pool.reorgOnNewHead(ctx, head)
+	m, r := txc.getLists()
+	pool.relay.NewHead(pool.head, m, r)
+	pool.homestead = pool.config.IsHomestead(head.Number)
+	pool.signer = types.MakeSigner(pool.config, head.Number)
+}
+
 // Stop stops the light transaction pool
 func (pool *TxPool) Stop() {
 	close(pool.quit)
diff --git a/light/txpool_test.go b/light/txpool_test.go
index 60d1256d41..0d091627af 100644
--- a/light/txpool_test.go
+++ b/light/txpool_test.go
@@ -17,6 +17,7 @@
 package light
 
 import (
+	"context"
 	"math"
 	"math/big"
 	"testing"
@@ -29,7 +30,6 @@ import (
 	"github.com/ubiq/go-ubiq/ethdb"
 	"github.com/ubiq/go-ubiq/event"
 	"github.com/ubiq/go-ubiq/params"
-	"golang.org/x/net/context"
 )
 
 type testTxRelay struct {
@@ -106,10 +106,11 @@ func TestTxPool(t *testing.T) {
 	lightchain.SetValidator(bproc{})
 	txPermanent = 50
 	pool := NewTxPool(testChainConfig(), evmux, lightchain, relay)
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+	defer cancel()
 
 	for ii, block := range gchain {
 		i := ii + 1
-		ctx, _ := context.WithTimeout(context.Background(), 200*time.Millisecond)
 		s := sentTx(i - 1)
 		e := sentTx(i)
 		for i := s; i < e; i++ {
diff --git a/light/vm_env.go b/light/vm_env.go
index bc98c7788f..e1aed2eee8 100644
--- a/light/vm_env.go
+++ b/light/vm_env.go
@@ -17,13 +17,13 @@
 package light
 
 import (
+	"context"
 	"math/big"
 
 	"github.com/ubiq/go-ubiq/common"
 	"github.com/ubiq/go-ubiq/core/types"
 	"github.com/ubiq/go-ubiq/core/vm"
 	"github.com/ubiq/go-ubiq/crypto"
-	"golang.org/x/net/context"
 )
 
 // VMState is a wrapper for the light state that holds the actual context and
diff --git a/mobile/context.go b/mobile/context.go
index 281419905c..7f87f7e6e1 100644
--- a/mobile/context.go
+++ b/mobile/context.go
@@ -14,15 +14,11 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-// Contains all the wrappers from the golang.org/x/net/context package to support
-// client side context management on mobile platforms.
-
 package gubiq
 
 import (
+	"context"
 	"time"
-
-	"golang.org/x/net/context"
 )
 
 // Context carries a deadline, a cancelation signal, and other values across API
diff --git a/rpc/client.go b/rpc/client.go
index 0dce933e37..532d8eaf93 100644
--- a/rpc/client.go
+++ b/rpc/client.go
@@ -19,6 +19,7 @@ package rpc
 import (
 	"bytes"
 	"container/list"
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -32,7 +33,6 @@ import (
 
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
-	"golang.org/x/net/context"
 )
 
 var (
diff --git a/rpc/client_context_go1.4.go b/rpc/client_context_go1.4.go
deleted file mode 100644
index ac956a17dd..0000000000
--- a/rpc/client_context_go1.4.go
+++ /dev/null
@@ -1,60 +0,0 @@
-// Copyright 2016 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-// +build !go1.5
-
-package rpc
-
-import (
-	"net"
-	"net/http"
-	"time"
-
-	"golang.org/x/net/context"
-)
-
-// In older versions of Go (below 1.5), dials cannot be canceled
-// via a channel or context. The context deadline can still applied.
-
-// contextDialer returns a dialer that applies the deadline value from the given context.
-func contextDialer(ctx context.Context) *net.Dialer {
-	dialer := &net.Dialer{KeepAlive: tcpKeepAliveInterval}
-	if deadline, ok := ctx.Deadline(); ok {
-		dialer.Deadline = deadline
-	} else {
-		dialer.Deadline = time.Now().Add(defaultDialTimeout)
-	}
-	return dialer
-}
-
-// dialContext connects to the given address, aborting the dial if ctx is canceled.
-func dialContext(ctx context.Context, network, addr string) (net.Conn, error) {
-	return contextDialer(ctx).Dial(network, addr)
-}
-
-// requestWithContext copies req, adding the cancelation channel and deadline from ctx.
-func requestWithContext(c *http.Client, req *http.Request, ctx context.Context) (*http.Client, *http.Request) {
-	// Set Timeout on the client if the context has a deadline.
-	// Note that there is no default timeout (unlike in contextDialer) because
-	// the timeout applies to the entire request, including reads from body.
-	if deadline, ok := ctx.Deadline(); ok {
-		c2 := *c
-		c2.Timeout = deadline.Sub(time.Now())
-		c = &c2
-	}
-	req2 := *req
-	return c, &req2
-}
diff --git a/rpc/client_context_go1.5.go b/rpc/client_context_go1.5.go
deleted file mode 100644
index 4a007d9f8a..0000000000
--- a/rpc/client_context_go1.5.go
+++ /dev/null
@@ -1,61 +0,0 @@
-// Copyright 2016 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-// +build go1.5,!go1.6
-
-package rpc
-
-import (
-	"net"
-	"net/http"
-	"time"
-
-	"golang.org/x/net/context"
-)
-
-// In Go 1.5, dials cannot be canceled via a channel or context. The context deadline can
-// still be applied. Go 1.5 adds the ability to cancel HTTP requests via a channel.
-
-// contextDialer returns a dialer that applies the deadline value from the given context.
-func contextDialer(ctx context.Context) *net.Dialer {
-	dialer := &net.Dialer{KeepAlive: tcpKeepAliveInterval}
-	if deadline, ok := ctx.Deadline(); ok {
-		dialer.Deadline = deadline
-	} else {
-		dialer.Deadline = time.Now().Add(defaultDialTimeout)
-	}
-	return dialer
-}
-
-// dialContext connects to the given address, aborting the dial if ctx is canceled.
-func dialContext(ctx context.Context, network, addr string) (net.Conn, error) {
-	return contextDialer(ctx).Dial(network, addr)
-}
-
-// requestWithContext copies req, adding the cancelation channel and deadline from ctx.
-func requestWithContext(c *http.Client, req *http.Request, ctx context.Context) (*http.Client, *http.Request) {
-	// Set Timeout on the client if the context has a deadline.
-	// Note that there is no default timeout (unlike in contextDialer) because
-	// the timeout applies to the entire request, including reads from body.
-	if deadline, ok := ctx.Deadline(); ok {
-		c2 := *c
-		c2.Timeout = deadline.Sub(time.Now())
-		c = &c2
-	}
-	req2 := *req
-	req2.Cancel = ctx.Done()
-	return c, &req2
-}
diff --git a/rpc/client_context_go1.6.go b/rpc/client_context_go1.6.go
deleted file mode 100644
index 67777ddc6a..0000000000
--- a/rpc/client_context_go1.6.go
+++ /dev/null
@@ -1,55 +0,0 @@
-// Copyright 2016 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-// +build go1.6,!go1.7
-
-package rpc
-
-import (
-	"net"
-	"net/http"
-	"time"
-
-	"golang.org/x/net/context"
-)
-
-// In Go 1.6, net.Dialer gained the ability to cancel via a channel.
-
-// contextDialer returns a dialer that applies the deadline value from the given context.
-func contextDialer(ctx context.Context) *net.Dialer {
-	dialer := &net.Dialer{Cancel: ctx.Done(), KeepAlive: tcpKeepAliveInterval}
-	if deadline, ok := ctx.Deadline(); ok {
-		dialer.Deadline = deadline
-	} else {
-		dialer.Deadline = time.Now().Add(defaultDialTimeout)
-	}
-	return dialer
-}
-
-// dialContext connects to the given address, aborting the dial if ctx is canceled.
-func dialContext(ctx context.Context, network, addr string) (net.Conn, error) {
-	return contextDialer(ctx).Dial(network, addr)
-}
-
-// requestWithContext copies req, adding the cancelation channel and deadline from ctx.
-func requestWithContext(c *http.Client, req *http.Request, ctx context.Context) (*http.Client, *http.Request) {
-	// We set Timeout on the client for Go <= 1.5. There
-	// is no need to do that here because the dial will be canceled
-	// by package http.
-	req2 := *req
-	req2.Cancel = ctx.Done()
-	return c, &req2
-}
diff --git a/rpc/client_context_go1.7.go b/rpc/client_context_go1.7.go
deleted file mode 100644
index 56ce12ab8e..0000000000
--- a/rpc/client_context_go1.7.go
+++ /dev/null
@@ -1,51 +0,0 @@
-// Copyright 2016 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-// +build go1.7
-
-package rpc
-
-import (
-	"context"
-	"net"
-	"net/http"
-	"time"
-)
-
-// In Go 1.7, context moved into the standard library and support
-// for cancelation via context was added to net.Dialer and http.Request.
-
-// contextDialer returns a dialer that applies the deadline value from the given context.
-func contextDialer(ctx context.Context) *net.Dialer {
-	dialer := &net.Dialer{Cancel: ctx.Done(), KeepAlive: tcpKeepAliveInterval}
-	if deadline, ok := ctx.Deadline(); ok {
-		dialer.Deadline = deadline
-	} else {
-		dialer.Deadline = time.Now().Add(defaultDialTimeout)
-	}
-	return dialer
-}
-
-// dialContext connects to the given address, aborting the dial if ctx is canceled.
-func dialContext(ctx context.Context, network, addr string) (net.Conn, error) {
-	d := &net.Dialer{KeepAlive: tcpKeepAliveInterval}
-	return d.DialContext(ctx, network, addr)
-}
-
-// requestWithContext copies req, adding the cancelation channel and deadline from ctx.
-func requestWithContext(c *http.Client, req *http.Request, ctx context.Context) (*http.Client, *http.Request) {
-	return c, req.WithContext(ctx)
-}
diff --git a/rpc/client_example_test.go b/rpc/client_example_test.go
index 3d72f5714a..b3a4711a3a 100644
--- a/rpc/client_example_test.go
+++ b/rpc/client_example_test.go
@@ -17,12 +17,12 @@
 package rpc_test
 
 import (
+	"context"
 	"fmt"
 	"math/big"
 	"time"
 
 	"github.com/ubiq/go-ubiq/rpc"
-	"golang.org/x/net/context"
 )
 
 // In this example, our client whishes to track the latest 'block number'
diff --git a/rpc/client_test.go b/rpc/client_test.go
index 3b965245e9..777a1ab769 100644
--- a/rpc/client_test.go
+++ b/rpc/client_test.go
@@ -17,6 +17,7 @@
 package rpc
 
 import (
+	"context"
 	"fmt"
 	"math/rand"
 	"net"
@@ -32,7 +33,6 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
-	"golang.org/x/net/context"
 )
 
 func TestClientRequest(t *testing.T) {
diff --git a/rpc/http.go b/rpc/http.go
index 7d4fe5d474..96ae942748 100644
--- a/rpc/http.go
+++ b/rpc/http.go
@@ -18,6 +18,7 @@ package rpc
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -29,7 +30,6 @@ import (
 	"time"
 
 	"github.com/rs/cors"
-	"golang.org/x/net/context"
 )
 
 const (
@@ -115,11 +115,11 @@ func (hc *httpConn) doRequest(ctx context.Context, msg interface{}) (io.ReadClos
 	if err != nil {
 		return nil, err
 	}
-	client, req := requestWithContext(hc.client, hc.req, ctx)
+	req := hc.req.WithContext(ctx)
 	req.Body = ioutil.NopCloser(bytes.NewReader(body))
 	req.ContentLength = int64(len(body))
 
-	resp, err := client.Do(req)
+	resp, err := hc.client.Do(req)
 	if err != nil {
 		return nil, err
 	}
diff --git a/rpc/inproc.go b/rpc/inproc.go
index f72b974977..595a7ca651 100644
--- a/rpc/inproc.go
+++ b/rpc/inproc.go
@@ -17,9 +17,8 @@
 package rpc
 
 import (
+	"context"
 	"net"
-
-	"golang.org/x/net/context"
 )
 
 // NewInProcClient attaches an in-process connection to the given RPC server.
diff --git a/rpc/ipc.go b/rpc/ipc.go
index b0273105da..f7b5996565 100644
--- a/rpc/ipc.go
+++ b/rpc/ipc.go
@@ -17,11 +17,11 @@
 package rpc
 
 import (
+	"context"
 	"net"
 
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
-	"golang.org/x/net/context"
 )
 
 // CreateIPCListener creates an listener, on Unix platforms this is a unix socket, on
diff --git a/rpc/ipc_unix.go b/rpc/ipc_unix.go
index a25b216277..0851ea61e1 100644
--- a/rpc/ipc_unix.go
+++ b/rpc/ipc_unix.go
@@ -19,11 +19,10 @@
 package rpc
 
 import (
+	"context"
 	"net"
 	"os"
 	"path/filepath"
-
-	"golang.org/x/net/context"
 )
 
 // ipcListen will create a Unix socket on the given endpoint.
diff --git a/rpc/ipc_windows.go b/rpc/ipc_windows.go
index 68234d2151..ca56a3ce43 100644
--- a/rpc/ipc_windows.go
+++ b/rpc/ipc_windows.go
@@ -19,10 +19,10 @@
 package rpc
 
 import (
+	"context"
 	"net"
 	"time"
 
-	"golang.org/x/net/context"
 	"gopkg.in/natefinch/npipe.v2"
 )
 
diff --git a/rpc/server.go b/rpc/server.go
index e3ef3ef0fe..72a3f27202 100644
--- a/rpc/server.go
+++ b/rpc/server.go
@@ -17,6 +17,7 @@
 package rpc
 
 import (
+	"context"
 	"fmt"
 	"reflect"
 	"runtime"
@@ -24,7 +25,6 @@ import (
 
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
-	"golang.org/x/net/context"
 	"gopkg.in/fatih/set.v0"
 )
 
diff --git a/rpc/server_test.go b/rpc/server_test.go
index c3c88fab75..90d62f26d8 100644
--- a/rpc/server_test.go
+++ b/rpc/server_test.go
@@ -17,13 +17,12 @@
 package rpc
 
 import (
+	"context"
 	"encoding/json"
 	"net"
 	"reflect"
 	"testing"
 	"time"
-
-	"golang.org/x/net/context"
 )
 
 type Service struct{}
diff --git a/rpc/subscription.go b/rpc/subscription.go
index bcdc3cdfca..9ab6af9e14 100644
--- a/rpc/subscription.go
+++ b/rpc/subscription.go
@@ -17,10 +17,9 @@
 package rpc
 
 import (
+	"context"
 	"errors"
 	"sync"
-
-	"golang.org/x/net/context"
 )
 
 var (
diff --git a/rpc/subscription_test.go b/rpc/subscription_test.go
index 00c4e0e354..345b4e5f29 100644
--- a/rpc/subscription_test.go
+++ b/rpc/subscription_test.go
@@ -17,13 +17,12 @@
 package rpc
 
 import (
+	"context"
 	"encoding/json"
 	"net"
 	"sync"
 	"testing"
 	"time"
-
-	"golang.org/x/net/context"
 )
 
 type NotificationTestService struct {
diff --git a/rpc/utils.go b/rpc/utils.go
index c249e9b4a8..2506c48331 100644
--- a/rpc/utils.go
+++ b/rpc/utils.go
@@ -18,6 +18,7 @@ package rpc
 
 import (
 	"bufio"
+	"context"
 	crand "crypto/rand"
 	"encoding/binary"
 	"encoding/hex"
@@ -29,8 +30,6 @@ import (
 	"time"
 	"unicode"
 	"unicode/utf8"
-
-	"golang.org/x/net/context"
 )
 
 var (
diff --git a/rpc/websocket.go b/rpc/websocket.go
index 67e693f184..674d1a9826 100644
--- a/rpc/websocket.go
+++ b/rpc/websocket.go
@@ -17,6 +17,7 @@
 package rpc
 
 import (
+	"context"
 	"crypto/tls"
 	"fmt"
 	"net"
@@ -24,10 +25,10 @@ import (
 	"net/url"
 	"os"
 	"strings"
+	"time"
 
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
-	"golang.org/x/net/context"
 	"golang.org/x/net/websocket"
 	"gopkg.in/fatih/set.v0"
 )
@@ -150,3 +151,18 @@ func wsDialAddress(location *url.URL) string {
 	}
 	return location.Host
 }
+
+func dialContext(ctx context.Context, network, addr string) (net.Conn, error) {
+	d := &net.Dialer{KeepAlive: tcpKeepAliveInterval}
+	return d.DialContext(ctx, network, addr)
+}
+
+func contextDialer(ctx context.Context) *net.Dialer {
+	dialer := &net.Dialer{Cancel: ctx.Done(), KeepAlive: tcpKeepAliveInterval}
+	if deadline, ok := ctx.Deadline(); ok {
+		dialer.Deadline = deadline
+	} else {
+		dialer.Deadline = time.Now().Add(defaultDialTimeout)
+	}
+	return dialer
+}
diff --git a/swarm/services/swap/swap.go b/swarm/services/swap/swap.go
index c87d707144..5ef8f3929b 100644
--- a/swarm/services/swap/swap.go
+++ b/swarm/services/swap/swap.go
@@ -17,6 +17,7 @@
 package swap
 
 import (
+	"context"
 	"crypto/ecdsa"
 	"fmt"
 	"math/big"
@@ -34,7 +35,6 @@ import (
 	"github.com/ubiq/go-ubiq/logger"
 	"github.com/ubiq/go-ubiq/logger/glog"
 	"github.com/ubiq/go-ubiq/swarm/services/swap/swap"
-	"golang.org/x/net/context"
 )
 
 // SwAP       Swarm Accounting Protocol with
diff --git a/swarm/swarm.go b/swarm/swarm.go
index 2fe0f67711..21bd1c88f8 100644
--- a/swarm/swarm.go
+++ b/swarm/swarm.go
@@ -18,6 +18,7 @@ package swarm
 
 import (
 	"bytes"
+	"context"
 	"crypto/ecdsa"
 	"fmt"
 
@@ -36,7 +37,6 @@ import (
 	httpapi "github.com/ubiq/go-ubiq/swarm/api/http"
 	"github.com/ubiq/go-ubiq/swarm/network"
 	"github.com/ubiq/go-ubiq/swarm/storage"
-	"golang.org/x/net/context"
 )
 
 // the swarm stack
diff --git a/vendor.conf b/vendor.conf
index 286d8121b7..e9ee32dcb8 100644
--- a/vendor.conf
+++ b/vendor.conf
@@ -40,5 +40,3 @@ gopkg.in/natefinch/npipe.v2	c1b8fa8
 gopkg.in/sourcemap.v1	v1.0.3
 gopkg.in/urfave/cli.v1	v1.19.1
 
-# exclude
--golang.org/x/net/context
diff --git a/vendor/github.com/Azure/azure-sdk-for-go/.travis.yml b/vendor/github.com/Azure/azure-sdk-for-go/.travis.yml
index 6a134afebf..679d3167d2 100644
--- a/vendor/github.com/Azure/azure-sdk-for-go/.travis.yml
+++ b/vendor/github.com/Azure/azure-sdk-for-go/.travis.yml
@@ -7,7 +7,6 @@ go: 1.7
 install:
   - go get -u github.com/golang/lint/golint
   - go get -u github.com/Masterminds/glide
-  - go get -u golang.org/x/net/context
   - go get -u github.com/HewlettPackard/gas
   - go get -u gopkg.in/godo.v2/cmd/godo
   - export GO15VENDOREXPERIMENT=1
diff --git a/vendor/github.com/rs/cors/cors.go b/vendor/github.com/rs/cors/cors.go
index 4bb22d8fce..849ab6e1f8 100644
--- a/vendor/github.com/rs/cors/cors.go
+++ b/vendor/github.com/rs/cors/cors.go
@@ -21,6 +21,7 @@ The resulting handler is a standard net/http handler.
 package cors
 
 import (
+	"context"
 	"log"
 	"net/http"
 	"os"
@@ -28,7 +29,6 @@ import (
 	"strings"
 
 	"github.com/rs/xhandler"
-	"golang.org/x/net/context"
 )
 
 // Options is a configuration container to setup the CORS middleware.
diff --git a/vendor/github.com/rs/xhandler/chain.go b/vendor/github.com/rs/xhandler/chain.go
index 3e4bd359c5..80ce0e9dab 100644
--- a/vendor/github.com/rs/xhandler/chain.go
+++ b/vendor/github.com/rs/xhandler/chain.go
@@ -1,9 +1,8 @@
 package xhandler
 
 import (
+	"context"
 	"net/http"
-
-	"golang.org/x/net/context"
 )
 
 // Chain is a helper for chaining middleware handlers together for easier
diff --git a/vendor/github.com/rs/xhandler/middleware.go b/vendor/github.com/rs/xhandler/middleware.go
index 7ad8fba625..11c7e6171a 100644
--- a/vendor/github.com/rs/xhandler/middleware.go
+++ b/vendor/github.com/rs/xhandler/middleware.go
@@ -1,10 +1,9 @@
 package xhandler
 
 import (
+	"context"
 	"net/http"
 	"time"
-
-	"golang.org/x/net/context"
 )
 
 // CloseHandler returns a Handler, cancelling the context when the client
diff --git a/vendor/github.com/rs/xhandler/xhandler.go b/vendor/github.com/rs/xhandler/xhandler.go
index bc832cb1fa..04faeef454 100644
--- a/vendor/github.com/rs/xhandler/xhandler.go
+++ b/vendor/github.com/rs/xhandler/xhandler.go
@@ -12,9 +12,8 @@
 package xhandler // import "github.com/rs/xhandler"
 
 import (
+	"context"
 	"net/http"
-
-	"golang.org/x/net/context"
 )
 
 // HandlerC is a net/context aware http.Handler