diff --git a/Kconfig b/Kconfig
index c52f781..1bd33af 100644
--- a/Kconfig
+++ b/Kconfig
@@ -14,7 +14,7 @@ config TTN_LORA_FREQ_EU_868
     bool "Europe (868 MHz)"
 
 config TTN_LORA_FREQ_US_915
-    bool "North America (915 MHz)"
+    bool "North and South America (915 MHz)"
 
 config TTN_LORA_FREQ_AU_921
     bool "Australia (921 MHz)"
@@ -25,6 +25,9 @@ config TTN_LORA_FREQ_AS_923
 config TTN_LORA_FREQ_AS_923_JP
     bool "Asia, region Japan (923 MHz)"
 
+config TTN_LORA_FREQ_KR_920
+    bool "South Korea (920 MHz)"
+
 config TTN_LORA_FREQ_IN_866
     bool "India (866 MHz)"
 
diff --git a/src/aes/lmic_aes.c b/src/aes/lmic_aes.c
old mode 100755
new mode 100644
diff --git a/src/aes/other.c b/src/aes/other.c
old mode 100755
new mode 100644
diff --git a/esp_idf_lmic_config.h b/src/esp_idf_lmic_config.h
similarity index 96%
rename from esp_idf_lmic_config.h
rename to src/esp_idf_lmic_config.h
index d4798c8..7b08a13 100755
--- a/esp_idf_lmic_config.h
+++ b/src/esp_idf_lmic_config.h
@@ -23,6 +23,8 @@
 #elif defined(CONFIG_TTN_LORA_FREQ_AS_923_JP)
 #define CFG_as923 1
 #define LMIC_COUNTRY_CODE LMIC_COUNTRY_CODE_JP
+#elif defined(CONFIG_TTN_LORA_FREQ_KR_920)
+#define CFG_kr920 1
 #elif defined(CONFIG_TTN_LORA_FREQ_IN_866)
 #define CFG_in866 1
 #else
diff --git a/src/lmic/config.h b/src/lmic/config.h
old mode 100755
new mode 100644
diff --git a/src/lmic/hal.h b/src/lmic/hal.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic.c b/src/lmic/lmic.c
old mode 100755
new mode 100644
index e431e8c..7a1beec
--- a/src/lmic/lmic.c
+++ b/src/lmic/lmic.c
@@ -1872,7 +1872,7 @@ static bit_t buildDataFrame (void) {
         LMIC.adrChanged = 0;
     }
 
-    u1_t flen = end + (txdata ? 5+dlen : 4);
+    unsigned int flen = end + (txdata ? 5+dlen : 4);
     if( flen > MAX_LEN_FRAME ) {
         // Options and payload too big - delay payload
         txdata = 0;
diff --git a/src/lmic/lmic.h b/src/lmic/lmic.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_as923.c b/src/lmic/lmic_as923.c
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_au921.c b/src/lmic/lmic_au921.c
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_bandplan.h b/src/lmic/lmic_bandplan.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_bandplan_as923.h b/src/lmic/lmic_bandplan_as923.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_bandplan_au921.h b/src/lmic/lmic_bandplan_au921.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_bandplan_eu868.h b/src/lmic/lmic_bandplan_eu868.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_bandplan_in866.h b/src/lmic/lmic_bandplan_in866.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_bandplan_kr920.h b/src/lmic/lmic_bandplan_kr920.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_bandplan_us915.h b/src/lmic/lmic_bandplan_us915.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_compliance.c b/src/lmic/lmic_compliance.c
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_compliance.h b/src/lmic/lmic_compliance.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_config_preconditions.h b/src/lmic/lmic_config_preconditions.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_env.h b/src/lmic/lmic_env.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_eu868.c b/src/lmic/lmic_eu868.c
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_eu_like.c b/src/lmic/lmic_eu_like.c
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_eu_like.h b/src/lmic/lmic_eu_like.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_in866.c b/src/lmic/lmic_in866.c
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_kr920.c b/src/lmic/lmic_kr920.c
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_us915.c b/src/lmic/lmic_us915.c
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_us_like.c b/src/lmic/lmic_us_like.c
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_us_like.h b/src/lmic/lmic_us_like.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_util.c b/src/lmic/lmic_util.c
old mode 100755
new mode 100644
diff --git a/src/lmic/lmic_util.h b/src/lmic/lmic_util.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lorabase.h b/src/lmic/lorabase.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lorabase_as923.h b/src/lmic/lorabase_as923.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lorabase_au921.h b/src/lmic/lorabase_au921.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lorabase_eu868.h b/src/lmic/lorabase_eu868.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lorabase_in866.h b/src/lmic/lorabase_in866.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lorabase_kr920.h b/src/lmic/lorabase_kr920.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lorabase_us915.h b/src/lmic/lorabase_us915.h
old mode 100755
new mode 100644
diff --git a/src/lmic/lorawan_spec_compliance.h b/src/lmic/lorawan_spec_compliance.h
old mode 100755
new mode 100644
diff --git a/src/lmic/oslmic.c b/src/lmic/oslmic.c
old mode 100755
new mode 100644
diff --git a/src/lmic/oslmic.h b/src/lmic/oslmic.h
old mode 100755
new mode 100644
diff --git a/src/lmic/oslmic_types.h b/src/lmic/oslmic_types.h
old mode 100755
new mode 100644
diff --git a/src/lmic/radio.c b/src/lmic/radio.c
old mode 100755
new mode 100644