diff --git a/device.h b/device.h
index 7d1fda9..ab67164 100755
--- a/device.h
+++ b/device.h
@@ -5,7 +5,7 @@
 
 // Version info
 #define MAJ_VERSION  0x01
-#define MIN_VERSION  0x00
+#define MIN_VERSION  0x01
 
 // CPU settings
 #define TARGET_CPU m1284p
@@ -99,4 +99,14 @@
 	#define USR_IO_4	4
 #endif
 
+// File system paths
+#define PATH_BASE "OpenModem"
+#define PATH_LOG "OpenModem/Log"
+#define PATH_LOG_INDEX "OpenModem/Log/packet.index"
+
+#define PATH_ENTROPY_INDEX "OpenModem/entropy.index"
+#define PATH_ENTROPY_SOURCE "OpenModem/entropy.source"
+#define PATH_AES_128_KEY "OpenModem/aes128.key"
+#define PATH_CRYPTO_DISABLE "OpenModem/aes128.disable"
+
 #endif
\ No newline at end of file
diff --git a/hardware/Crypto.c b/hardware/Crypto.c
index 8f85462..9ea1ca7 100644
--- a/hardware/Crypto.c
+++ b/hardware/Crypto.c
@@ -152,7 +152,8 @@ bool update_entropy_index(void) {
 
 		UINT written = 0;
 		crypto_fr = f_write(&crypto_fp, crypto_fb, sizeof(entropy_index), &written);
-
+		f_close(&crypto_fp);
+		
 		if (crypto_fr == FR_OK && written == sizeof(entropy_index)) {
 			return true;
 		}
diff --git a/hardware/Crypto.h b/hardware/Crypto.h
index e819b30..ed9036f 100644
--- a/hardware/Crypto.h
+++ b/hardware/Crypto.h
@@ -10,11 +10,6 @@
 #include "hardware/LED.h"
 #include "hardware/SD.h"
 
-#define PATH_ENTROPY_INDEX "OpenModem/entropy.index"
-#define PATH_ENTROPY_SOURCE "OpenModem/entropy.source"
-#define PATH_AES_128_KEY "OpenModem/aes128.key"
-#define PATH_CRYPTO_DISABLE "OpenModem/aes128.disable"
-
 #define CRYPTO_KEY_SIZE_BITS 128
 #define CRYPTO_KEY_SIZE (CRYPTO_KEY_SIZE_BITS/8)
 #define CRYPTO_HMAC_SIZE_BITS 128
diff --git a/protocol/KISS.c b/protocol/KISS.c
index ec2dcc6..e3864a5 100755
--- a/protocol/KISS.c
+++ b/protocol/KISS.c
@@ -36,6 +36,14 @@ bool ESCAPE;
 
 uint8_t command = CMD_UNKNOWN;
 
+bool log_ready = false;
+uint32_t log_index = 0;
+FIL log_fp;
+char log_fb[4];
+char log_filename[32];
+FRESULT log_fr;
+FILINFO log_fi;
+
 void kiss_init(AX25Ctx *ax25, Afsk *afsk, Serial *ser) {
     ax25ctx = ax25;
     serial = ser;
@@ -125,6 +133,21 @@ void kiss_messageCallback(AX25Ctx *ctx) {
         }
 
         if (integrity_ok) {
+            bool log_write_ok = false;
+            if (config_log_packets && sd_mounted()) {
+                if (log_ready || log_init()) {
+                    // TODO: Assertion here on max path length
+                    memset(log_filename, 0x00, sizeof(log_filename));
+                    snprintf(log_filename, sizeof(log_filename), "%s/%lu.pkt", PATH_LOG, log_index);
+                    
+                    // Open file descriptor
+                    log_fr = f_open(&log_fp, log_filename, FA_CREATE_NEW | FA_WRITE);
+                    if (log_fr == FR_OK) {
+                        log_write_ok = true;
+                    }
+                }
+            }
+
             fputc(FEND, &serial->uart0);
             fputc(0x00, &serial->uart0);
             for (unsigned i = 0; i < ctx->frame_len-2; i++) {
@@ -138,12 +161,106 @@ void kiss_messageCallback(AX25Ctx *ctx) {
                 } else {
                     fputc(b, &serial->uart0);
                 }
+                if (log_write_ok) {
+                    UINT written = 0;
+                    log_fr = f_write(&log_fp, &b, 1, &written);
+                }
             }
             fputc(FEND, &serial->uart0);
+
+            if (config_log_packets && sd_mounted() && log_ready) {
+                f_close(&log_fp);
+                update_log_index();
+            }
         }
     #endif
 }
 
+bool log_init(void) {
+    if (sd_mounted()) {
+        // Check that base dir exists
+        log_fr = f_stat(PATH_BASE, &log_fi);
+        if (log_fr == FR_NO_PATH || log_fr == FR_NO_FILE) {
+            log_fr = f_mkdir(PATH_BASE);
+            if (log_fr != FR_OK) {
+                return false;
+            } else {
+            }
+        }
+
+        // Check that log dir exists
+        log_fr = f_stat(PATH_LOG, &log_fi);
+        if (log_fr == FR_NO_PATH || log_fr == FR_NO_FILE) {
+            log_fr = f_mkdir(PATH_LOG);
+            if (log_fr != FR_OK) {
+                return false;
+            }
+        }
+
+        if (load_log_index()) {
+            log_ready = true;
+            return true;
+        } else {
+            return false;
+        }
+        
+    } else {
+        return false;
+    }
+}
+
+bool load_log_index(void) {
+    if (sd_mounted()) {
+        log_fr = f_open(&log_fp, PATH_LOG_INDEX, FA_READ);
+        if (log_fr == FR_NO_FILE) {
+            f_close(&log_fp);
+            log_fr = f_open(&log_fp, PATH_LOG_INDEX, FA_CREATE_NEW | FA_WRITE);
+
+            if (log_fr == FR_OK) {
+                log_index = 0x00000000;
+                memcpy(log_fb, &log_index, sizeof(log_index));
+                
+                UINT written = 0;
+                log_fr = f_write(&log_fp, log_fb, sizeof(log_index), &written);
+                f_close(&log_fp);
+            }
+
+            log_fr = f_open(&log_fp, PATH_LOG_INDEX, FA_READ);
+        }
+
+        if (log_fr == FR_OK) {
+            UINT read = 0;
+            log_fr = f_read(&log_fp, log_fb, sizeof(log_index), &read);
+            f_close(&log_fp);
+            if (log_fr == FR_OK && read == sizeof(log_index)) {
+                memcpy(&log_index, log_fb, sizeof(log_index));
+                return true;
+            }
+        }
+    }
+
+    f_close(&log_fp);
+    return false;
+}
+
+bool update_log_index(void) {
+    log_fr = f_open(&log_fp, PATH_LOG_INDEX, FA_WRITE);
+    if (log_fr == FR_OK) {
+        log_index++;
+        memcpy(log_fb, &log_index, sizeof(log_index));
+
+        UINT written = 0;
+        log_fr = f_write(&log_fp, log_fb, sizeof(log_index), &written);
+
+        f_close(&log_fp);
+
+        if (log_fr == FR_OK && written == sizeof(log_index)) {
+            return true;
+        }
+    }
+    return false;
+}
+
 void kiss_csma(void) {
     if (queue_height > 0) {
         #if BITRATE == 2400
diff --git a/protocol/KISS.h b/protocol/KISS.h
index 9f2dcc2..c65071c 100755
--- a/protocol/KISS.h
+++ b/protocol/KISS.h
@@ -48,4 +48,8 @@ void kiss_output_modem_mode(void);
 void kiss_output_config(uint8_t* data, size_t length);
 void kiss_output_afsk_peak(void);
 
+bool log_init(void);
+bool load_log_index(void);
+bool update_log_index(void);
+
 #endif
\ No newline at end of file