diff --git a/chain/types/message.go b/chain/types/message.go
index cbc7c1dad..c53ecc7c1 100644
--- a/chain/types/message.go
+++ b/chain/types/message.go
@@ -195,7 +195,7 @@ func (m *Message) ValidForBlockInclusion(minGas int64) error {
 
 	// since prices might vary with time, this is technically semantic validation
 	if m.GasLimit < minGas {
-		return xerrors.New("'GasLimit' field cannot be less than the cost of storing a message on chain")
+		return xerrors.Errorf("'GasLimit' field cannot be less than the cost of storing a message on chain %d < %d", m.GasLimit, minGas)
 	}
 
 	return nil
diff --git a/chain/types/signedmessage.go b/chain/types/signedmessage.go
index 7532bea35..c539ac240 100644
--- a/chain/types/signedmessage.go
+++ b/chain/types/signedmessage.go
@@ -78,7 +78,14 @@ func (sm *SignedMessage) MarshalJSON() ([]byte, error) {
 }
 
 func (sm *SignedMessage) ChainLength() int {
-	ser, err := sm.Serialize()
+	var ser []byte
+	var err error
+	if sm.Signature.Type == crypto.SigTypeBLS {
+		// BLS chain message length doesn't include signature
+		ser, err = sm.Message.Serialize()
+	} else {
+		ser, err = sm.Serialize()
+	}
 	if err != nil {
 		panic(err)
 	}