diff --git a/txscript/opcode.go b/txscript/opcode.go
index 3c147ae39..145e7b775 100644
--- a/txscript/opcode.go
+++ b/txscript/opcode.go
@@ -287,7 +287,7 @@ const (
 	OP_UNKNOWN246          = 0xf6 // 246
 	OP_UNKNOWN247          = 0xf7 // 247
 	OP_UNKNOWN248          = 0xf8 // 248
-	OP_SMALLDATA           = 0xf9 // 249 - bitcoin core internal
+	OP_UNKNOWN249          = 0xf9 // 249
 	OP_SMALLINTEGER        = 0xfa // 250 - bitcoin core internal
 	OP_PUBKEYS             = 0xfb // 251 - bitcoin core internal
 	OP_UNKNOWN252          = 0xfc // 252
@@ -573,9 +573,9 @@ var opcodeArray = [256]opcode{
 	OP_UNKNOWN246: {OP_UNKNOWN246, "OP_UNKNOWN246", 1, opcodeInvalid},
 	OP_UNKNOWN247: {OP_UNKNOWN247, "OP_UNKNOWN247", 1, opcodeInvalid},
 	OP_UNKNOWN248: {OP_UNKNOWN248, "OP_UNKNOWN248", 1, opcodeInvalid},
+	OP_UNKNOWN249: {OP_UNKNOWN249, "OP_UNKNOWN249", 1, opcodeInvalid},
 
 	// Bitcoin Core internal use opcode.  Defined here for completeness.
-	OP_SMALLDATA:    {OP_SMALLDATA, "OP_SMALLDATA", 1, opcodeInvalid},
 	OP_SMALLINTEGER: {OP_SMALLINTEGER, "OP_SMALLINTEGER", 1, opcodeInvalid},
 	OP_PUBKEYS:      {OP_PUBKEYS, "OP_PUBKEYS", 1, opcodeInvalid},
 	OP_UNKNOWN252:   {OP_UNKNOWN252, "OP_UNKNOWN252", 1, opcodeInvalid},
diff --git a/txscript/opcode_test.go b/txscript/opcode_test.go
index c9bdfa5d5..969ce674d 100644
--- a/txscript/opcode_test.go
+++ b/txscript/opcode_test.go
@@ -74,8 +74,8 @@ func TestOpcodeDisasm(t *testing.T) {
 		0xa9: "OP_HASH160", 0xaa: "OP_HASH256", 0xab: "OP_CODESEPARATOR",
 		0xac: "OP_CHECKSIG", 0xad: "OP_CHECKSIGVERIFY",
 		0xae: "OP_CHECKMULTISIG", 0xaf: "OP_CHECKMULTISIGVERIFY",
-		0xf9: "OP_SMALLDATA", 0xfa: "OP_SMALLINTEGER",
-		0xfb: "OP_PUBKEYS", 0xfd: "OP_PUBKEYHASH", 0xfe: "OP_PUBKEY",
+		0xfa: "OP_SMALLINTEGER", 0xfb: "OP_PUBKEYS",
+		0xfd: "OP_PUBKEYHASH", 0xfe: "OP_PUBKEY",
 		0xff: "OP_INVALIDOPCODE",
 	}
 	for opcodeVal, expectedStr := range expectedStrings {
@@ -122,7 +122,7 @@ func TestOpcodeDisasm(t *testing.T) {
 			}
 
 		// OP_UNKNOWN#.
-		case opcodeVal >= 0xba && opcodeVal <= 0xf8 || opcodeVal == 0xfc:
+		case opcodeVal >= 0xba && opcodeVal <= 0xf9 || opcodeVal == 0xfc:
 			expectedStr = "OP_UNKNOWN" + strconv.Itoa(int(opcodeVal))
 		}
 
@@ -188,7 +188,7 @@ func TestOpcodeDisasm(t *testing.T) {
 			}
 
 		// OP_UNKNOWN#.
-		case opcodeVal >= 0xba && opcodeVal <= 0xf8 || opcodeVal == 0xfc:
+		case opcodeVal >= 0xba && opcodeVal <= 0xf9 || opcodeVal == 0xfc:
 			expectedStr = "OP_UNKNOWN" + strconv.Itoa(int(opcodeVal))
 		}