diff --git a/core/vm/eips.go b/core/vm/eips.go
index 0e1cff0c49..89e76c0271 100644
--- a/core/vm/eips.go
+++ b/core/vm/eips.go
@@ -16,11 +16,15 @@
 
 package vm
 
-import "fmt"
+import (
+	"fmt"
+	
+	"github.com/ethereum/go-ethereum/params"
+)
 
 // EnableEIP enables the given EIP on the config.
-// This operation write in-place, and callers need to ensure that the globally
-// defined jumptables are not polluted
+// This operation writes in-place, and callers need to ensure that the globally
+// defined jump tables are not polluted.
 func EnableEIP(eipNum int, jt *JumpTable) error {
 	switch eipNum {
 	case 1884:
@@ -31,16 +35,17 @@ func EnableEIP(eipNum int, jt *JumpTable) error {
 	return nil
 }
 
-// Enable1884 applies EIP-1884 to the given jumptable
+// enable1884 applies EIP-1884 to the given jump table:
 // - Increase cost of BALANCE to 700
 // - Increase cost of EXTCODEHASH to 700
 // - Increase cost of SLOAD to 800
 // - Define SELFBALANCE, with cost GasFastStep (5)
 func enable1884(jt *JumpTable) {
 	// Gas cost changes
-	jt[BALANCE].constantGas = 700
-	jt[EXTCODEHASH].constantGas = 700
-	jt[SLOAD].constantGas = 800
+	jt[BALANCE].constantGas = params.BalanceGasEIP1884
+	jt[EXTCODEHASH].constantGas = params.ExtcodeHashGasEIP1884
+	jt[SLOAD].constantGas = params.SloadGasEIP1884
+
 	// New opcode
 	jt[SELFBALANCE] = operation{
 		execute:     opSelfBalance,
diff --git a/core/vm/interpreter.go b/core/vm/interpreter.go
index ae4a99539a..4a902dce52 100644
--- a/core/vm/interpreter.go
+++ b/core/vm/interpreter.go
@@ -110,7 +110,7 @@ func NewEVMInterpreter(evm *EVM, cfg Config) *EVMInterpreter {
 			if err := EnableEIP(eip, &jt); err != nil {
 				// Disable it, so caller can check if it's activated or not
 				cfg.ExtraEips = append(cfg.ExtraEips[:i], cfg.ExtraEips[i+1:]...)
-				log.Error("eip %d failed activation: %v", err)
+				log.Error("eip activation failed", "eip", eip, "error", err)
 			}
 		}
 		cfg.JumpTable = jt
diff --git a/core/vm/jump_table.go b/core/vm/jump_table.go
index bde9b76078..da532541c6 100644
--- a/core/vm/jump_table.go
+++ b/core/vm/jump_table.go
@@ -62,6 +62,7 @@ var (
 	constantinopleInstructionSet   = newConstantinopleInstructionSet()
 )
 
+// JumpTable contains the EVM opcodes supported at a given fork.
 type JumpTable [256]operation
 
 // NewConstantinopleInstructionSet returns the frontier, homestead
@@ -92,7 +93,7 @@ func newConstantinopleInstructionSet() JumpTable {
 	}
 	instructionSet[EXTCODEHASH] = operation{
 		execute:     opExtCodeHash,
-		constantGas: params.ExtcodeHashGas,
+		constantGas: params.ExtcodeHashGasConstantinople,
 		minStack:    minStack(1, 1),
 		maxStack:    maxStack(1, 1),
 		valid:       true,
diff --git a/params/protocol_params.go b/params/protocol_params.go
index 01dc197aff..fe8f18ee21 100644
--- a/params/protocol_params.go
+++ b/params/protocol_params.go
@@ -70,16 +70,19 @@ const (
 	TxDataNonZeroGas      uint64 = 68    // Per byte of data attached to a transaction that is not equal to zero. NOTE: Not payable on data of calls between transactions.
 
 	// These have been changed during the course of the chain
-	CallGasFrontier        uint64 = 40  // Once per CALL operation & message call transaction.
-	CallGasEIP150          uint64 = 700 // Static portion of gas for CALL-derivates after EIP 150 (Tangerine)
-	BalanceGasFrontier     uint64 = 20  // The cost of a BALANCE operation
-	BalanceGasEIP150       uint64 = 400 // The cost of a BALANCE operation after Tangerine
-	ExtcodeSizeGasFrontier uint64 = 20  // Cost of EXTCODESIZE before EIP 150 (Tangerine)
-	ExtcodeSizeGasEIP150   uint64 = 700 // Cost of EXTCODESIZE after EIP 150 (Tangerine)
-	SloadGasFrontier       uint64 = 50
-	SloadGasEIP150         uint64 = 200
-	ExtcodeHashGas         uint64 = 400  // Cost of EXTCODEHASH (introduced in Constantinople)
-	SelfdestructGasEIP150  uint64 = 5000 // Cost of SELFDESTRUCT post EIP 150 (Tangerine)
+	CallGasFrontier              uint64 = 40  // Once per CALL operation & message call transaction.
+	CallGasEIP150                uint64 = 700 // Static portion of gas for CALL-derivates after EIP 150 (Tangerine)
+	BalanceGasFrontier           uint64 = 20  // The cost of a BALANCE operation
+	BalanceGasEIP150             uint64 = 400 // The cost of a BALANCE operation after Tangerine
+	BalanceGasEIP1884            uint64 = 700 // The cost of a BALANCE operation after EIP 1884 (part of Istanbul)
+	ExtcodeSizeGasFrontier       uint64 = 20  // Cost of EXTCODESIZE before EIP 150 (Tangerine)
+	ExtcodeSizeGasEIP150         uint64 = 700 // Cost of EXTCODESIZE after EIP 150 (Tangerine)
+	SloadGasFrontier             uint64 = 50
+	SloadGasEIP150               uint64 = 200
+	SloadGasEIP1884              uint64 = 800  // Cost of SLOAD after EIP 1884 (part of Istanbul)
+	ExtcodeHashGasConstantinople uint64 = 400  // Cost of EXTCODEHASH (introduced in Constantinople)
+	ExtcodeHashGasEIP1884        uint64 = 700  // Cost of EXTCODEHASH after EIP 1884 (part in Istanbul)
+	SelfdestructGasEIP150        uint64 = 5000 // Cost of SELFDESTRUCT post EIP 150 (Tangerine)
 
 	// EXP has a dynamic portion depending on the size of the exponent
 	ExpByteFrontier uint64 = 10 // was set to 10 in Frontier