diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1c7adf3a6..69078a1f7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,8 @@ All notable changes to this project will be documented in this file.
 This project uses the changelog in accordance with [keepchangelog](http://keepachangelog.com/). Please use this to write notable changes, which is not the same as git commit log...
 
 ## [unreleased][unreleased]
+ - Fix 'hf mf fchk' (@iceman)
+ - Fix 'usb slow on posix based systems' (@fl0-0)
  - Change 'lf pcf7931' - improved read code (@sguerrini97)
  - Change 'hf felica list' - started with some FeliCa annotations (@iceman)
  - Fix 'hf tune' - now works as expected (@iceman)
diff --git a/armsrc/mifarecmd.c b/armsrc/mifarecmd.c
index 3e1967b4e..6b10ddd0d 100644
--- a/armsrc/mifarecmd.c
+++ b/armsrc/mifarecmd.c
@@ -1259,7 +1259,6 @@ void MifareChkKeys_fast(uint32_t arg0, uint32_t arg1, uint32_t arg2, uint8_t *da
 	LED_A_ON();
 		
 	if ( firstchunk ) {
-							
 		clear_trace();
 		set_tracing(false);
 		
@@ -1458,26 +1457,31 @@ void MifareChkKeys_fast(uint32_t arg0, uint32_t arg1, uint32_t arg2, uint8_t *da
 			} // end loop sectors		
 		} // end loop keys	
 	} // end loop strategy 2
-OUT:	
+OUT:
 	LEDsoff();
 
 	crypto1_destroy(pcs);
 
 	// All keys found, send to client, or last keychunk from client
 	if (foundkeys == allkeys || lastchunk ) {
-		
+
 		uint64_t foo = 0;
+		for (uint8_t m = 0; m < 64; m++) {
+			foo |= ((uint64_t)(found[m] & 1) << m);
+		}
+
 		uint16_t bar = 0;
-		for (uint8_t m = 0; m < 64; ++m)
-			foo |= (found[m] << m);
-		for (uint8_t m=64; m < sizeof(found); ++m) 
-			bar |= (found[m] << (m-64));
-		
+		uint8_t j = 0;
+		for (uint8_t m=64; m < sizeof(found); m++) {
+			bar |= ((uint16_t)(found[m] & 1) << j++);
+		}
+	
 		uint8_t *tmp =  BigBuf_malloc(480+10);
 		memcpy(tmp, k_sector, sectorcnt * sizeof(sector_t) );
 		num_to_bytes(foo, 8, tmp+480);		
 		tmp[488] = bar & 0xFF;
 		tmp[489] = bar >> 8 & 0xFF;
+		
 		cmd_send(CMD_ACK, foundkeys, 0, 0, tmp, 480+10);
 
 		set_tracing(false);		
diff --git a/client/mifarehost.c b/client/mifarehost.c
index 0f37f8a8b..31ed8e39d 100644
--- a/client/mifarehost.c
+++ b/client/mifarehost.c
@@ -173,18 +173,19 @@ int mfCheckKeys_fast( uint8_t sectorsCnt, uint8_t firstChunk, uint8_t lastChunk,
 		
 		// success array. each byte is status of key 
 		uint8_t arr[80];
-		uint64_t foo = bytes_to_num(resp.d.asBytes+480, 8);
-		for (uint8_t i = 0; i < 64;  ++i) {
-			arr[i] = (foo >> i) & 0x1;
-		}
-		foo = bytes_to_num(resp.d.asBytes+488, 2);
-		for (uint8_t i = 0; i < 16;  ++i) {
-			arr[i+64] = (foo >> i) & 0x1;
-		}
+		uint64_t foo = 0;
+		uint16_t bar = 0;
+		foo = bytes_to_num(resp.d.asBytes+480, 8);
+		bar = (resp.d.asBytes[489]  << 8 | resp.d.asBytes[488]);
 
+		for (uint8_t i = 0; i < 64; i++)
+			arr[i] = (foo >> i) & 0x1;
+	
+		for (uint8_t i = 0; i < 16; i++)
+			arr[i+64] = (bar >> i) & 0x1;
+		
 		// initialize storage for found keys
-		icesector_t *tmp = NULL;
-		tmp = calloc(sectorsCnt, sizeof(icesector_t));
+		icesector_t *tmp = calloc(sectorsCnt, sizeof(icesector_t));
 		if (tmp == NULL)
 			return 1;
 		memcpy(tmp, resp.d.asBytes, sectorsCnt * sizeof(icesector_t) );