diff --git a/contracts/utils.go b/contracts/utils.go
index 7dbf205a53..d664471501 100644
--- a/contracts/utils.go
+++ b/contracts/utils.go
@@ -355,7 +355,7 @@ func GetSignersSignedAtBlockHash(c *posv.Posv, chain consensus.ChainReader, data
 // Get signers list from bytes.
 func GetSignersFromBytes(byteHeader []byte) []common.Address {
 	signers := make([]common.Address, len(byteHeader)/common.AddressLength)
-	for i := 0; i < len(masternodes); i++ {
+	for i := 0; i < len(signers); i++ {
 		copy(signers[i][:], byteHeader[i*common.AddressLength:])
 	}
 
diff --git a/core/state_transition.go b/core/state_transition.go
index 1a5f6c0fd0..2fb9893d00 100644
--- a/core/state_transition.go
+++ b/core/state_transition.go
@@ -238,7 +238,7 @@ func (st *StateTransition) TransitionDb() (ret []byte, usedGas uint64, failed bo
 		contractAction = "contract creation"
 	} else {
 		// Increment the nonce for the next transaction
-		nonce = st.state.GetNonce(sender.Address())+1
+		nonce = st.state.GetNonce(sender.Address()) + 1
 		st.state.SetNonce(sender.Address(), nonce)
 		ret, st.gas, vmerr = evm.Call(sender, st.to().Address(), st.data, st.gas, st.value)
 		contractAction = "contract call"
diff --git a/eth/backend.go b/eth/backend.go
index 9a2f121394..514186692d 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -337,9 +337,7 @@ func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
 						}
 					}
 					if len(prevSigners) > 0 {
-						for _, signer := range prevSigners {
-							penSigners = append(penSigners, signer)
-						}
+						penSigners = append(penSigners, prevSigners...)
 					}
 				}
 
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index cda2f037ac..59f59972e5 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -683,7 +683,7 @@ func (s *PublicBlockChainAPI) GetMasternodes(b *types.Block, ctx context.Context
 			if prevCheckpointBlock != nil {
 				masternodes = engine.GetMasternodesFromCheckpointHeader(prevCheckpointBlock.Header(), curBlockNumber, s.b.ChainConfig().Posv.Epoch)
 			}
-		}  else {
+		} else {
 			log.Error("Undefined POSV consensus engine")
 		}
 	}
@@ -980,7 +980,7 @@ func (s *PublicBlockChainAPI) rpcOutputBlockSigners(b *types.Block, ctx context.
 					}
 				}
 			}
-		}  else {
+		} else {
 			log.Error("Undefined POSV consensus engine")
 		}
 	}