diff --git a/include/power.h b/include/power.h
index d11235c0..24ec9e28 100644
--- a/include/power.h
+++ b/include/power.h
@@ -34,6 +34,15 @@
 #endif
 #endif
 
+#ifdef EXT_POWER_SW
+#ifndef EXT_POWER_ON
+#define EXT_POWER_ON 1
+#endif
+#ifndef EXT_POWER_OFF
+#define EXT_POWER_OFF (!EXT_POWER_ON)
+#endif
+#endif
+
 typedef uint8_t (*mapFn_t)(uint16_t, uint16_t, uint16_t);
 
 uint16_t read_voltage(void);
diff --git a/src/hal/ecopower.h b/src/hal/ecopower.h
index 4b7f7a6f..276b3c54 100644
--- a/src/hal/ecopower.h
+++ b/src/hal/ecopower.h
@@ -20,7 +20,6 @@
 
 #define EXT_POWER_SW    15            // Switch VDD on pin JP10, needed for RTC DS3231
 #define EXT_POWER_ON    0
-#define EXT_POWER_OFF   1
 
 #define HAS_LED (2) // on board green LED
 #define HAS_TWO_LED (12) // on board red LED
diff --git a/src/hal/heltec.h b/src/hal/heltec.h
index 6cea89f7..47877577 100644
--- a/src/hal/heltec.h
+++ b/src/hal/heltec.h
@@ -8,6 +8,7 @@
 #include <stdint.h>
 
 // Hardware related definitions for Heltec V1 LoRa-32 Board
+// see https://heltec-automation-docs.readthedocs.io/en/latest/esp32/wifi_lora_32/hardware_update_log.html#v1
 
 //#define HAS_BME 1 // Enable BME sensors in general
 //#define HAS_BME680 GPIO_NUM_21, GPIO_NUM_22 // SDA, SCL
diff --git a/src/hal/heltecv2.h b/src/hal/heltecv2.h
index c57607e2..dce2c717 100644
--- a/src/hal/heltecv2.h
+++ b/src/hal/heltecv2.h
@@ -8,6 +8,7 @@
 #include <stdint.h>
 
 // Hardware related definitions for Heltec V2 LoRa-32 Board
+// see https://heltec-automation-docs.readthedocs.io/en/latest/esp32/wifi_lora_32/hardware_update_log.html#v2
 
 //#define HAS_BME 1 // Enable BME sensors in general
 //#define HAS_BME680 GPIO_NUM_4, GPIO_NUM_15 // SDA, SCL
@@ -29,9 +30,9 @@
 //#define BAT_MEASURE_ADC_UNIT 2 // ADC 2
 //#define BAT_VOLTAGE_DIVIDER 2 // voltage divider 220k/100k on board
 
-#define EXT_POWER_SW Vext // switches battery power, Vext control 0 = on / 1 = off
-#define EXT_POWER_ON    0
-//#define EXT_POWER_OFF   1
+// switches battery power and Vext, switch logic 0 = on / 1 = off
+#define EXT_POWER_SW Vext
+#define EXT_POWER_ON 0
 
 // Pins for I2C interface of OLED Display
 #define MY_DISPLAY_SDA SDA_OLED
@@ -43,7 +44,7 @@
 #define LORA_IRQ DIO0
 #define LORA_IO1 DIO1
 #define LORA_IO2 DIO2
-#define LORA_SCK GPIO_NUM_5
+#define LORA_SCK SCK
 #define LORA_MISO MISO
 #define LORA_MOSI MOSI
 #define LORA_RST RST_LoRa
diff --git a/src/hal/ttgofox.h b/src/hal/ttgofox.h
index d61460a8..dc0a9974 100644
--- a/src/hal/ttgofox.h
+++ b/src/hal/ttgofox.h
@@ -15,7 +15,6 @@
 
 #define EXT_POWER_SW GPIO_NUM_25 // switches power for LoRa chip
 #define EXT_POWER_ON    0
-#define EXT_POWER_OFF   1
 #define BAT_MEASURE_ADC ADC1_GPIO35_CHANNEL
 #define BAT_VOLTAGE_DIVIDER 2 // voltage divider 100k/100k on board
 #define HAS_BUTTON GPIO_NUM_36 // on board button (next to reset)