diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1a8720a223..70e2bbe24e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@ This project uses the changelog in accordance with [keepchangelog](http://keepac
 
 ## [unreleased][unreleased]
  - Added support for NTAG424 cards. (@dankar)
+ - Additional fixes to configcard code for keyroll mode based on nfc-iclass output (@Antiklesys)
  - Added `bind` option for network connections to specify the outbound address and port (@wh201906)
  - Changed `lf em 4x05 dump` - now supports the `--ns` nosave parameter (@iceman1001)
  - Fixed some wrong synchronization waits in usb_write() to increase the communication speed (@wh201906)
@@ -40,6 +41,7 @@ This project uses the changelog in accordance with [keepchangelog](http://keepac
  - Modified `hf iclass configcard` to only support online mode (@Antiklesys)
  - Modified `hf iclass configcard` command to generate config cards without a cardhelper module by porting the contents of blocks 6 & 7 from nfc-iclass (@Antiklesys)
  - Fixed `hf iclass info` command showing incorrectly in offline mode (@Antiklesys)
+ - Changed lf sampling - improved the performance (@yah01)
 
 ## [Raccoon.4.17140][2023-09-09]
  - Changed text and adjust pm3_test case for mf_aes_brute (@doegox)
diff --git a/armsrc/lfsampling.c b/armsrc/lfsampling.c
index 6c131e7f37..c763bd0c67 100644
--- a/armsrc/lfsampling.c
+++ b/armsrc/lfsampling.c
@@ -128,20 +128,6 @@ sample_config *getSamplingConfig(void) {
     return &config;
 }
 
-/**
- * @brief Pushes bit onto the stream
- * @param stream
- * @param bit
- */
-static void pushBit(BitstreamOut_t *stream, uint8_t bit) {
-    int bytepos = stream->position >> 3; // divide by 8
-    int bitpos = stream->position & 7;
-    *(stream->buffer + bytepos) &= ~(1 << (7 - bitpos));
-    *(stream->buffer + bytepos) |= (bit > 0) << (7 - bitpos);
-    stream->position++;
-    stream->numbits++;
-}
-
 void initSampleBuffer(uint32_t *sample_size) {
     initSampleBufferEx(sample_size, false);
 }
@@ -233,13 +219,20 @@ void logSample(uint8_t sample, uint8_t decimation, uint8_t bits_per_sample, bool
         data.numbits = samples.total_saved << 3;
 
     } else {
-        pushBit(&data, sample & 0x80);
-        if (bits_per_sample > 1) pushBit(&data, sample & 0x40);
-        if (bits_per_sample > 2) pushBit(&data, sample & 0x20);
-        if (bits_per_sample > 3) pushBit(&data, sample & 0x10);
-        if (bits_per_sample > 4) pushBit(&data, sample & 0x08);
-        if (bits_per_sample > 5) pushBit(&data, sample & 0x04);
-        if (bits_per_sample > 6) pushBit(&data, sample & 0x02);
+        // truncate trailing data
+        sample >>= 8 - bits_per_sample;
+        sample <<= 8 - bits_per_sample;
+
+        uint8_t bits_offset = data.numbits & 0x7;
+        uint8_t bits_cap = 8 - bits_offset;
+
+        // write the current byte
+        data.buffer[data.numbits >> 3] |= sample >> bits_offset;
+        int numbits = data.numbits + bits_cap;
+
+        // write the remaining bits to the next byte
+        data.buffer[numbits >> 3] |= sample << (bits_cap);
+        data.numbits += bits_per_sample;
     }
 }
 
diff --git a/client/src/cmdhficlass.c b/client/src/cmdhficlass.c
index 3966f85178..98065f2d05 100644
--- a/client/src/cmdhficlass.c
+++ b/client/src/cmdhficlass.c
@@ -424,7 +424,7 @@ static int generate_config_card(const iclass_config_card_item_t *o,  uint8_t *ke
             memcpy(data + (0x0D * 8), lkey, sizeof(enckey1));
         }
         // encrypted 0xFF
-        for (uint8_t i = 0x0D; i < 0x14; i++) {
+        for (uint8_t i = 0x0E; i < 0x14; i++) {
             memcpy(data + (i * 8), ffs, sizeof(ffs));
         }
         PrintAndLogEx(NORMAL, "( " _GREEN_("ok") " )");
@@ -450,7 +450,7 @@ static int generate_config_card(const iclass_config_card_item_t *o,  uint8_t *ke
         // encrypted partial keyroll key 15
         PrintAndLogEx(INFO, "Setting encrypted partial key15... " NOLF);
         memset(foo, 0xFF, sizeof(foo));
-        foo[0] = lkey[7];
+        foo[0] = key[7];
         if (IsCardHelperPresent(false) != false) {
             if (Encrypt(foo, enckey2) == false) {
                 PrintAndLogEx(WARNING, "failed to encrypt partial 2");