diff --git a/armsrc/Standalone/hf_tmudford.c b/armsrc/Standalone/hf_tmudford.c
index 158250a0c..a945a49ec 100644
--- a/armsrc/Standalone/hf_tmudford.c
+++ b/armsrc/Standalone/hf_tmudford.c
@@ -75,7 +75,8 @@ void RunMod(void) {
             } else if (state == STATE_EMUL) {
                 Iso15693InitTag();
                 Dbprintf("Starting simulation, press pm3-button to stop and go back to search state.");
-                SimTagIso15693(card.uid);
+                // default block size is 4
+                SimTagIso15693(card.uid, 4);
 
                 state = STATE_READ;
             }