diff --git a/src/bitcoin.c b/src/bitcoin.c
index b114fd06..0888302a 100644
--- a/src/bitcoin.c
+++ b/src/bitcoin.c
@@ -146,8 +146,10 @@ bool gen_gbtbase(connsock_t *cs, gbtbase_t *gbt)
 	coinbasevalue = json_integer_value(json_object_get(res_val, "coinbasevalue"));
 	coinbase_aux = json_object_get(res_val, "coinbaseaux");
 	flags = json_string_value(json_object_get(coinbase_aux, "flags"));
+	if (!flags)
+		flags = "";
 
-	if (unlikely(!previousblockhash || !target || !version || !curtime || !bits || !coinbase_aux || !flags)) {
+	if (unlikely(!previousblockhash || !target || !version || !curtime || !bits || !coinbase_aux)) {
 		LOGERR("JSON failed to decode GBT %s %s %d %d %s %s", previousblockhash, target, version, curtime, bits, flags);
 		goto out;
 	}