diff --git a/eth/filters/api.go b/eth/filters/api.go
index 945b99f484..61eddcc662 100644
--- a/eth/filters/api.go
+++ b/eth/filters/api.go
@@ -22,7 +22,6 @@ import (
 	"errors"
 	"fmt"
 	"math/big"
-	"strings"
 	"sync"
 	"time"
 
@@ -476,11 +475,11 @@ func returnLogs(logs []*types.Log) []*types.Log {
 // UnmarshalJSON sets *args fields with given data.
 func (args *FilterCriteria) UnmarshalJSON(data []byte) error {
 	type input struct {
-		BlockHash *common.Hash  `json:"blockHash"`
-		FromBlock *string       `json:"fromBlock"`
-		ToBlock   *string       `json:"toBlock"`
-		Addresses interface{}   `json:"address"`
-		Topics    []interface{} `json:"topics"`
+		BlockHash *common.Hash           `json:"blockHash"`
+		FromBlock *rpc.BlockNumberOrHash `json:"fromBlock"`
+		ToBlock   *rpc.BlockNumberOrHash `json:"toBlock"`
+		Addresses interface{}            `json:"address"`
+		Topics    []interface{}          `json:"topics"`
 	}
 
 	var raw input
@@ -496,19 +495,17 @@ func (args *FilterCriteria) UnmarshalJSON(data []byte) error {
 		args.BlockHash = raw.BlockHash
 	} else {
 		if raw.FromBlock != nil {
-			if strings.HasPrefix(*raw.FromBlock, "0x") {
-				hash := common.HexToHash(*raw.FromBlock)
-				args.FromBlockHash = &hash
+			if raw.FromBlock.IsHash() {
+				args.FromBlockHash = raw.FromBlock.Hash()
 			} else {
-				args.FromBlock.UnmarshalJSON([]byte(*raw.FromBlock))
+				args.FromBlock = big.NewInt(int64(raw.FromBlock.Number()))
 			}
 		}
 		if raw.ToBlock != nil {
-			if strings.HasPrefix(*raw.ToBlock, "0x") {
-				hash := common.HexToHash(*raw.ToBlock)
-				args.ToBlockHash = &hash
+			if raw.ToBlock.IsHash() {
+				args.ToBlockHash = raw.ToBlock.Hash()
 			} else {
-				args.ToBlock.UnmarshalJSON([]byte(*raw.ToBlock))
+				args.ToBlock = big.NewInt(int64(raw.ToBlock.Number()))
 			}
 		}
 	}
diff --git a/eth/filters/filter.go b/eth/filters/filter.go
index b114ba9ad0..b2aad2e41e 100644
--- a/eth/filters/filter.go
+++ b/eth/filters/filter.go
@@ -223,18 +223,18 @@ func (f *Filter) Logs(ctx context.Context) ([]*types.Log, error) {
 	// Gather all indexed logs, and finish with non indexed ones
 	if mainChain {
 		size, sections := f.backend.BloomStatus()
-		if indexed := sections * size; indexed > begin.Number.Uint64() {
+		if indexed := sections * size; indexed > ancestor.Number.Uint64() {
 			if indexed > end.Number.Uint64() {
-				logs, err = f.indexedLogs(ctx, begin.Number.Uint64(), end.Number.Uint64())
+				logs, err = f.indexedLogs(ctx, ancestor.Number.Uint64(), end.Number.Uint64())
 			} else {
-				logs, err = f.indexedLogs(ctx, begin.Number.Uint64(), indexed-1)
+				logs, err = f.indexedLogs(ctx, ancestor.Number.Uint64(), indexed-1)
 			}
 			if err != nil {
 				return logs, err
 			}
 		}
 	}
-	rest, err := f.unindexedLogs(ctx, begin.Hash(), end.Hash())
+	rest, err := f.unindexedLogs(ctx, ancestor.Hash(), end.Hash())
 	logs = append(logs, rest...)
 	sort.Sort(logList(logs))
 
diff --git a/rpc/types.go b/rpc/types.go
index 4252c36027..0b09763f1d 100644
--- a/rpc/types.go
+++ b/rpc/types.go
@@ -24,6 +24,7 @@ import (
 	"sync"
 
 	mapset "github.com/deckarep/golang-set"
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 )
 
@@ -163,3 +164,28 @@ func (bn *BlockNumber) UnmarshalJSON(data []byte) error {
 func (bn BlockNumber) Int64() int64 {
 	return (int64)(bn)
 }
+
+type BlockNumberOrHash string
+
+func (bnh *BlockNumberOrHash) UnmarshalJSON(data []byte) error {
+	*bnh = BlockNumberOrHash(data)
+	return nil
+}
+
+func (bnh BlockNumberOrHash) IsHash() bool {
+	return bnh[0] == '"' && bnh[len(bnh)-1] == '"' && len(bnh) == 44
+}
+
+func (bnh BlockNumberOrHash) Hash() *common.Hash {
+	if !bnh.IsHash() {
+		return nil
+	}
+	hash := common.HexToHash(string(bnh[1 : len(bnh)-1]))
+	return &hash
+}
+
+func (bnh BlockNumberOrHash) Number() int64 {
+	var bn BlockNumber
+	(&bn).UnmarshalJSON([]byte(bnh))
+	return bn.Int64()
+}