diff --git a/src/hal/ttgov21.h b/src/hal/ttgov21.h
index 96617e1f..7ec2a7d4 100644
--- a/src/hal/ttgov21.h
+++ b/src/hal/ttgov21.h
@@ -1,12 +1,19 @@
-// Hardware related definitions for TTGO V2.1 Board
+/*  Hardware related definitions for TTGO V2.1 Board
+/ ATTENTION: check your board version!
+/ Different versions are on the market which need different settings in this file:
+/ - without label        -> "old"
+/ - labelled v1.5 on pcb -> "old"
+/ - labelled v1.6 on pcb -> "new"
+*/
+
 
 #define CFG_sx1276_radio 1 // HPD13A LoRa SoC
 
 #define HAS_DISPLAY U8X8_SSD1306_128X64_NONAME_HW_I2C
 #define DISPLAY_FLIP  1 // rotated display
-#define HAS_LED GPIO_NUM_23 // green on board LED_G3 (not in initial board version)
-#define HAS_BATTERY_PROBE ADC1_GPIO35_CHANNEL // battery probe GPIO pin -> ADC1_CHANNEL_7
-#define BATT_FACTOR 2 // voltage divider 100k/100k on board
+#define HAS_LED GPIO_NUM_23 // green on board LED (new board  ONLY)
+#define HAS_BATTERY_PROBE ADC1_GPIO35_CHANNEL // uses GPIO7 (new board ONLY)
+#define BATT_FACTOR 2 // voltage divider 100k/100k on board (new board  ONLY)
 
 // re-define pin definitions of pins_arduino.h
 #define PIN_SPI_SS    GPIO_NUM_18 // ESP32 GPIO18 (Pin18) -- HPD13A NSS/SEL (Pin4) SPI Chip Select Input
@@ -15,7 +22,9 @@
 #define PIN_SPI_SCK   GPIO_NUM_5  // ESP32 GPIO5 (Pin5)   -- HPD13A SCK (Pin5) SPI Clock Input
 
 // non arduino pin definitions
-#define RST   LMIC_UNUSED_PIN // connected to ESP32 RST/EN
+#define RST   LMIC_UNUSED_PIN // connected to ESP32 RST/EN (old board)
+//#define RST   GPIO_NUM_12 // connected to ESP32 RST/EN (old board v1.5)
+//#define RST   GPIO_NUM_19 // connected to ESP32 RST/EN (new board)
 #define DIO0  GPIO_NUM_26 // ESP32 GPIO26 <-> HPD13A IO0
 #define DIO1  GPIO_NUM_33 // ESP32 GPIO33 <-> HPDIO1 <-> HPD13A IO1
 #define DIO2  GPIO_NUM_32 // ESP32 GPIO32 <-> HPDIO2 <-> HPD13A IO2