diff --git a/client/proxmark3.c b/client/proxmark3.c
index 48f3d7b3e..ab78ceb41 100644
--- a/client/proxmark3.c
+++ b/client/proxmark3.c
@@ -91,10 +91,12 @@ bool hookUpPM3() {
 
 	if (sp == INVALID_SERIAL_PORT) {
 		PrintAndLogEx(WARNING, "Reconnect failed, retrying...  (reason: invalid serial port)\n");
+		sp = NULL;
 		ret = false;
 		offline = 1;
 	} else if (sp == CLAIMED_SERIAL_PORT) {
 		PrintAndLogEx(WARNING, "Reconnect failed, retrying... (reason: serial port is claimed by another process)\n");
+		sp = NULL;
 		ret = false;
 		offline = 1;
 	} else {