fix "hf felica raw" length of buffer calculations. Added some more comments to explain whats going on. Thanks to @dxl for the solutions!

Author: iceman1001

CHANGELOG.md

@@ -3,6 +3,7 @@ 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 felica raw` - wrong length calculationes. Thanks @dxl for the solutions! (@iceman1001)
 - Added basic QR code generation support. Thanks @mistial-dev for the idea! (@iceman1001)
 - Added identification of NDEF/Open print tag record (@iceman1001)
 - Added support for Bruce dump files [.rfid] (@iceman1001)

armsrc/felica.c

@@ -572,26 +572,31 @@ void felica_sendraw(const PacketCommandNG *c) {
 
     if ((param & FELICA_RAW) == FELICA_RAW) {
 
-        // 2 sync, 1 len, 2crc == 5
+        // 2 sync, 1 len, 2 crc == 5
         uint8_t *buf = BigBuf_calloc(len + 5);
         // add sync bits
         buf[0] = 0xb2;
         buf[1] = 0x4d;
-        buf[2] = len;
+
+        // len (number of bytes) + 1 for len byte itself
+        buf[2] = len + 1;
 
         // copy command
-        memcpy(buf + 2, c->data.asBytes, len);
+        memcpy(buf + 3, c->data.asBytes, len);
 
         if ((param & FELICA_APPEND_CRC) == FELICA_APPEND_CRC) {
             // Don't append crc on empty bytearray...
-            if (len > 0) {
-                AddCrc(buf + 2, len);
+            if (len) {
+                // n bytes + len 1 byte
+                AddCrc(buf + 2, len + 1);
             }
         }
 
         if (g_dbglevel >= DBG_DEBUG) {
             Dbprintf("Transmit Frame (no CRC shown):");
-            Dbhexdump(len, buf, 0);
+            // 0,1,2, n  
+            Dbhexdump(len + 1 + 2, buf, 0);
+            // total buffer length:   len + 1 len byte + 2 sync bytes + 2 crc bytes
             Dbprintf("Buffer Length: %i", buf[2] + 4);
         };