diff --git a/client/cmdhfmf.c b/client/cmdhfmf.c
index 13cbee685..820fb93bc 100644
--- a/client/cmdhfmf.c
+++ b/client/cmdhfmf.c
@@ -1081,7 +1081,7 @@ int CmdHF14AMfChk(const char *Cmd) {
 	char filename[FILE_PATH_SIZE]={0};
 	char buf[13];
 	uint8_t *keyBlock = NULL, *p;
-	uint8_t stKeyBlock = 20;
+	uint16_t stKeyBlock = 20;
 	
 	sector_t *e_sector = NULL;