diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index 81e20472..8c3293a6 100644
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -450,7 +450,7 @@ static RAMFUNC int ManchesterDecoding(int v)
 			Demod.syncBit = 0x02;
 		}
 
-		if(bit & 0x01) {
+		if(bit & 0x01 && Demod.syncBit) {
 			Demod.syncBit = 0x01;
 		}