diff --git a/client/src/cmdhfmf.c b/client/src/cmdhfmf.c
index 12799b25f..335898ef1 100644
--- a/client/src/cmdhfmf.c
+++ b/client/src/cmdhfmf.c
@@ -308,7 +308,6 @@ static int mf_print_keys(uint16_t n, uint8_t *d) {
     }
 
     for (uint16_t i = 0; i < n; i++) {
-
         if (mfIsSectorTrailer(i)) {
             e_sector[mfSectorNum(i)].foundKey[0] = 1;
             e_sector[mfSectorNum(i)].Key[0] = bytes_to_num(d + (i * MFBLOCK_SIZE), MIFARE_KEY_SIZE);
diff --git a/client/src/mifare/mifare4.c b/client/src/mifare/mifare4.c
index f42111ba8..ec8d1a6bf 100644
--- a/client/src/mifare/mifare4.c
+++ b/client/src/mifare/mifare4.c
@@ -530,7 +530,7 @@ uint8_t mfSectorTrailerOfSector(uint8_t sectorNo) {
 }
 
 // assumes blockno is 0-255..
-uint8_t mfSectorTrailer(uint8_t blockNo) {
+uint8_t mfSectorTrailer(uint16_t blockNo) {
     if (blockNo < 32 * 4) {
         return (blockNo | 0x03);
     } else {
@@ -539,15 +539,15 @@ uint8_t mfSectorTrailer(uint8_t blockNo) {
 }
 
 // assumes blockno is 0-255..
-bool mfIsSectorTrailer(uint8_t blockNo) {
+bool mfIsSectorTrailer(uint16_t blockNo) {
     return (blockNo == mfSectorTrailer(blockNo));
 }
 
 // assumes blockno is 0-255..
-uint8_t mfSectorNum(uint8_t blockNo) {
+uint8_t mfSectorNum(uint16_t blockNo) {
     if (blockNo < 32 * 4)
-        return blockNo / 4;
+        return (blockNo / 4);
     else
-        return 32 + (blockNo - 32 * 4) / 16;
+        return (32 + (blockNo - 32 * 4) / 16);
 
 }
diff --git a/client/src/mifare/mifare4.h b/client/src/mifare/mifare4.h
index 489add9f3..80d55db7b 100644
--- a/client/src/mifare/mifare4.h
+++ b/client/src/mifare/mifare4.h
@@ -77,9 +77,9 @@ const char *mfGetAccessConditionsDesc(uint8_t blockn, const uint8_t *data);
 uint8_t mfNumBlocksPerSector(uint8_t sectorNo);
 uint8_t mfFirstBlockOfSector(uint8_t sectorNo);
 uint8_t mfSectorTrailerOfSector(uint8_t sectorNo);
-uint8_t mfSectorTrailer(uint8_t blockNo);
-bool mfIsSectorTrailer(uint8_t blockNo);
-uint8_t mfSectorNum(uint8_t blockNo);
+uint8_t mfSectorTrailer(uint16_t blockNo);
+bool mfIsSectorTrailer(uint16_t blockNo);
+uint8_t mfSectorNum(uint16_t blockNo);
 
 
 #endif // mifare4.h