diff --git a/client/cmdhf14a.c b/client/cmdhf14a.c
index 93566f34b..219fb7c0c 100644
--- a/client/cmdhf14a.c
+++ b/client/cmdhf14a.c
@@ -501,11 +501,14 @@ int CmdHF14AInfo(const char *Cmd) {
 	
 	detect_classic_magic();
 	
-	if (isMifareClassic) {		
-		if ( detect_classic_prng() )
-			PrintAndLog("Prng detection: WEAK");
+	if (isMifareClassic) {
+		int res = detect_classic_prng();
+		if ( res == 1 )
+			PrintAndLog("[+] prng detection: WEAK");
+		else if (res == 0 )
+			PrintAndLog("[+] prng detection: HARDEND (hardnested)");
 		else
-			PrintAndLog("Prng detection: HARDEND (hardnested)");
+			PrintAndLog("[-] prng detection: failed");
 		
 		if ( do_nack_test )
 			detect_classic_nackbug(silent);
diff --git a/client/mifarehost.c b/client/mifarehost.c
index 26956e6a7..a29039c40 100644
--- a/client/mifarehost.c
+++ b/client/mifarehost.c
@@ -851,7 +851,7 @@ int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data,
 *	TRUE if tag uses WEAK prng (ie Now the NACK bug also needs to be present for Darkside attack)
 *   FALSE is tag uses HARDEND prng (ie hardnested attack possible, with known key)
 */
-bool detect_classic_prng(void){
+int detect_classic_prng(void){
 
 	UsbCommand resp, respA;	
 	uint8_t cmd[] = {MIFARE_AUTH_KEYA, 0x00};
@@ -865,23 +865,23 @@ bool detect_classic_prng(void){
 	
 	if (!WaitForResponseTimeout(CMD_ACK, &resp, 2000)) {
         PrintAndLog("[!] PRNG UID: Reply timeout.");
-		return false;
+		return -1;
 	}
 		
 	// if select tag failed.
 	if ( resp.arg[0] == 0 ) {
 		printf("[!] error:  selecting tag failed,  can't detect prng\n");
-		return false;
+		return -2;
 	}
 	if (!WaitForResponseTimeout(CMD_ACK, &respA, 2500)) {
         PrintAndLog("[!] PRNG data: Reply timeout.");
-		return false;
+		return -3;
 	}
 
 	// check respA
 	if (respA.arg[0] != 4) {
 		PrintAndLog("[!] PRNG data error: Wrong length: %d", respA.arg[0]);
-		return false;
+		return -4;
 	}			
 
 	uint32_t nonce = bytes_to_num(respA.d.asBytes, respA.arg[0]);
diff --git a/client/mifarehost.h b/client/mifarehost.h
index 27db5c1d5..0ee1504bd 100644
--- a/client/mifarehost.h
+++ b/client/mifarehost.h
@@ -98,7 +98,7 @@ extern int loadTraceCard(uint8_t *tuid, uint8_t uidlen);
 extern int saveTraceCard(void);
 extern int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len);
 
-extern bool detect_classic_prng(void);
+extern int detect_classic_prng(void);
 extern int detect_classic_nackbug(bool verbose);
 extern void detect_classic_magic(void);
 extern void mf_crypto1_decrypt(struct Crypto1State *pcs, uint8_t *data, int len, bool isEncrypted);
diff --git a/client/scripting.c b/client/scripting.c
index 86e0248c8..db864aebe 100644
--- a/client/scripting.c
+++ b/client/scripting.c
@@ -591,11 +591,13 @@ static int l_hardnested(lua_State *L){
 
 /**
  * @brief l_validate_prng is a function to test is a nonce is using the weak PRNG
+ * detection =  1 == weak,  0 == hard ,  -1 = failed
  * @param L
  * @return
  */
 static int l_detect_prng(lua_State *L) {
-	lua_pushboolean(L, detect_classic_prng());
+	int res = detect_classic_prng();
+	lua_pushinteger(L, res);
 	return 1;
 }
 /*
diff --git a/client/scripts/mifare_autopwn.lua b/client/scripts/mifare_autopwn.lua
index ae32b5c66..9bd149a55 100644
--- a/client/scripts/mifare_autopwn.lua
+++ b/client/scripts/mifare_autopwn.lua
@@ -111,10 +111,12 @@ end
 -- performs a test if tag nonce uses weak or hardend prng
 local function perform_prng_test()
 	local isweak = core.detect_prng()
-	if isweak then
+	if isweak == 1 then
 		dbg('PRNG detection : WEAK nonce detected')
-	else
+	elseif isweak == 0 then
 		dbg('PRNG detection : HARDEND nonce detected')
+	else
+		dbg('PRNG detection : failed')	
 	end
 	return isweak
 end
@@ -149,7 +151,7 @@ local function main(args)
 			seen_uids[uid] = uid
 			
 			-- check if PRNG is WEAK
-			if perform_prng_test() then  
+			if perform_prng_test() == 1 then  
 				print("Card found, commencing crack on UID", uid)
 
 				if #key == 12 then