diff --git a/Makefile b/Makefile
index 03b74853e..496243e49 100644
--- a/Makefile
+++ b/Makefile
@@ -559,12 +559,12 @@ CFLAGS		 = $(ARCH_FLAGS) \
 		   -D'__TARGET__="$(TARGET)"' \
 		   -D'__REVISION__="$(REVISION)"' \
 		   -save-temps=obj \
-		   -MMD
+		   -MMD -MP
 
 ASFLAGS		 = $(ARCH_FLAGS) \
 		   -x assembler-with-cpp \
 		   $(addprefix -I,$(INCLUDE_DIRS)) \
-		  -MMD
+		  -MMD -MP
 
 LDFLAGS		 = -lm \
 		   -nostartfiles \
diff --git a/src/main/blackbox/blackbox.c b/src/main/blackbox/blackbox.c
index ae9476297..0b7c06d8f 100644
--- a/src/main/blackbox/blackbox.c
+++ b/src/main/blackbox/blackbox.c
@@ -27,6 +27,7 @@
 #include "common/axis.h"
 #include "common/color.h"
 #include "common/encoding.h"
+#include "common/utils.h"
 
 #include "drivers/gpio.h"
 #include "drivers/sensor.h"
@@ -88,11 +89,6 @@
     typedef char assert_failed_ ## name [(condition) ? 1 : -1 ]
 
 // Some macros to make writing FLIGHT_LOG_FIELD_* constants shorter:
-#define STR_HELPER(x) #x
-#define STR(x) STR_HELPER(x)
-
-#define CONCAT_HELPER(x,y) x ## y
-#define CONCAT(x,y) CONCAT_HELPER(x, y)
 
 #define PREDICT(x) CONCAT(FLIGHT_LOG_FIELD_PREDICTOR_, x)
 #define ENCODING(x) CONCAT(FLIGHT_LOG_FIELD_ENCODING_, x)
diff --git a/src/main/common/utils.h b/src/main/common/utils.h
index d9f22c01e..90e12ac75 100644
--- a/src/main/common/utils.h
+++ b/src/main/common/utils.h
@@ -21,6 +21,12 @@
 
 #define ARRAYLEN(x) (sizeof(x) / sizeof((x)[0]))
 
+#define CONCAT_HELPER(x,y) x ## y
+#define CONCAT(x,y) CONCAT_HELPER(x, y)
+
+#define STR_HELPER(x) #x
+#define STR(x) STR_HELPER(x)
+
 /*
 http://resnet.uoregon.edu/~gurney_j/jmpc/bitwise.html
 */
diff --git a/src/main/config/config.c b/src/main/config/config.c
index 81645078d..c8d44d675 100644
--- a/src/main/config/config.c
+++ b/src/main/config/config.c
@@ -720,16 +720,12 @@ void validateAndFixConfig(void)
 
 #if defined(LED_STRIP) && (defined(USE_SOFTSERIAL1) || defined(USE_SOFTSERIAL2))
     if (feature(FEATURE_SOFTSERIAL) && (
+            0
 #ifdef USE_SOFTSERIAL1
-            (LED_STRIP_TIMER == SOFTSERIAL_1_TIMER)
-#else
-            0
+            || (LED_STRIP_TIMER == SOFTSERIAL_1_TIMER)
 #endif
-            ||
 #ifdef USE_SOFTSERIAL2
-            (LED_STRIP_TIMER == SOFTSERIAL_2_TIMER)
-#else
-            0
+            || (LED_STRIP_TIMER == SOFTSERIAL_2_TIMER)
 #endif
     )) {
         // led strip needs the same timer as softserial
diff --git a/src/main/drivers/adc.c b/src/main/drivers/adc.c
index 958a831b4..bdc7a6774 100644
--- a/src/main/drivers/adc.c
+++ b/src/main/drivers/adc.c
@@ -24,6 +24,7 @@
 #include "system.h"
 
 #include "adc.h"
+#include "adc_impl.h"
 
 //#define DEBUG_ADC_CHANNELS
 
diff --git a/src/main/drivers/adc_impl.h b/src/main/drivers/adc_impl.h
new file mode 100644
index 000000000..800730825
--- /dev/null
+++ b/src/main/drivers/adc_impl.h
@@ -0,0 +1,21 @@
+/*
+ * This file is part of Cleanflight.
+ *
+ * Cleanflight is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Cleanflight is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+extern adc_config_t adcConfig[ADC_CHANNEL_COUNT];
+extern volatile uint16_t adcValues[ADC_CHANNEL_COUNT];
diff --git a/src/main/drivers/adc_stm32f10x.c b/src/main/drivers/adc_stm32f10x.c
index c6c97c2f4..2becc32df 100644
--- a/src/main/drivers/adc_stm32f10x.c
+++ b/src/main/drivers/adc_stm32f10x.c
@@ -31,6 +31,7 @@
 #include "accgyro.h"
 
 #include "adc.h"
+#include "adc_impl.h"
 
 // Driver for STM32F103CB onboard ADC
 //
@@ -43,8 +44,6 @@
 //
 // CC3D Only one ADC channel supported currently, for battery on S5_IN/PA0
 
-extern adc_config_t adcConfig[ADC_CHANNEL_COUNT];
-extern volatile uint16_t adcValues[ADC_CHANNEL_COUNT];
 
 void adcInit(drv_adc_config_t *init)
 {
diff --git a/src/main/drivers/adc_stm32f30x.c b/src/main/drivers/adc_stm32f30x.c
index c18b37417..3b2fa1859 100644
--- a/src/main/drivers/adc_stm32f30x.c
+++ b/src/main/drivers/adc_stm32f30x.c
@@ -28,9 +28,7 @@
 #include "accgyro.h"
 
 #include "adc.h"
-
-extern adc_config_t adcConfig[ADC_CHANNEL_COUNT];
-extern volatile uint16_t adcValues[ADC_CHANNEL_COUNT];
+#include "adc_impl.h"
 
 #ifndef ADC_INSTANCE
 #define ADC_INSTANCE                ADC1
diff --git a/src/main/drivers/bus_i2c_stm32f10x.c b/src/main/drivers/bus_i2c_stm32f10x.c
index fa0e27c43..026dccf50 100644
--- a/src/main/drivers/bus_i2c_stm32f10x.c
+++ b/src/main/drivers/bus_i2c_stm32f10x.c
@@ -184,7 +184,7 @@ bool i2cRead(uint8_t addr_, uint8_t reg_, uint8_t len, uint8_t* buf)
 static void i2c_er_handler(void)
 {
     // Read the I2Cx status register
-    volatile uint32_t SR1Register = I2Cx->SR1;
+    uint32_t SR1Register = I2Cx->SR1;
 
     if (SR1Register & 0x0F00) {                                         // an error
         error = true;
@@ -325,6 +325,9 @@ void i2cInit(I2CDevice index)
     I2Cx_index = index;
     RCC_APB1PeriphClockCmd(i2cHardwareMap[index].peripheral, ENABLE);
 
+    // diable I2C interrrupts first to avoid ER handler triggering
+    I2C_ITConfig(I2Cx, I2C_IT_EVT | I2C_IT_ERR, DISABLE);
+
     // clock out stuff to make sure slaves arent stuck
     // This will also configure GPIO as AF_OD at the end
     i2cUnstick();
@@ -333,7 +336,7 @@ void i2cInit(I2CDevice index)
     I2C_DeInit(I2Cx);
     I2C_StructInit(&i2c);
 
-    I2C_ITConfig(I2Cx, I2C_IT_EVT | I2C_IT_ERR, DISABLE);               // Enable EVT and ERR interrupts - they are enabled by the first request
+    I2C_ITConfig(I2Cx, I2C_IT_EVT | I2C_IT_ERR, DISABLE);               // Disable EVT and ERR interrupts - they are enabled by the first request
     i2c.I2C_Mode = I2C_Mode_I2C;
     i2c.I2C_DutyCycle = I2C_DutyCycle_2;
     i2c.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
diff --git a/src/main/drivers/inverter.h b/src/main/drivers/inverter.h
index 81bd43295..017df613b 100644
--- a/src/main/drivers/inverter.h
+++ b/src/main/drivers/inverter.h
@@ -18,11 +18,11 @@
 #pragma once
 
 #ifdef INVERTER
-#define INVERTER_OFF digitalLo(INVERTER_GPIO, INVERTER_PIN);
-#define INVERTER_ON digitalHi(INVERTER_GPIO, INVERTER_PIN);
+#define INVERTER_OFF digitalLo(INVERTER_GPIO, INVERTER_PIN)
+#define INVERTER_ON digitalHi(INVERTER_GPIO, INVERTER_PIN)
 #else
-#define INVERTER_OFF ;
-#define INVERTER_ON ;
+#define INVERTER_OFF do {} while(0)
+#define INVERTER_ON do {} while(0)
 #endif
 
 void initInverter(void);
diff --git a/src/main/drivers/light_led.h b/src/main/drivers/light_led.h
index 8f62bd5ab..cf6a2bea9 100644
--- a/src/main/drivers/light_led.h
+++ b/src/main/drivers/light_led.h
@@ -19,49 +19,49 @@
 
 // Helpful macros
 #ifdef LED0
-#define LED0_TOGGLE              digitalToggle(LED0_GPIO, LED0_PIN);
+#define LED0_TOGGLE              digitalToggle(LED0_GPIO, LED0_PIN)
 #ifndef LED0_INVERTED
-#define LED0_OFF                 digitalHi(LED0_GPIO, LED0_PIN);
-#define LED0_ON                  digitalLo(LED0_GPIO, LED0_PIN);
+#define LED0_OFF                 digitalHi(LED0_GPIO, LED0_PIN)
+#define LED0_ON                  digitalLo(LED0_GPIO, LED0_PIN)
 #else
-#define LED0_OFF                 digitalLo(LED0_GPIO, LED0_PIN);
-#define LED0_ON                  digitalHi(LED0_GPIO, LED0_PIN);
+#define LED0_OFF                 digitalLo(LED0_GPIO, LED0_PIN)
+#define LED0_ON                  digitalHi(LED0_GPIO, LED0_PIN)
 #endif // inverted
 #else
-#define LED0_TOGGLE
-#define LED0_OFF
-#define LED0_ON
+#define LED0_TOGGLE              do {} while(0)
+#define LED0_OFF                 do {} while(0)
+#define LED0_ON                  do {} while(0)
 #endif
 
 #ifdef LED1
-#define LED1_TOGGLE              digitalToggle(LED1_GPIO, LED1_PIN);
+#define LED1_TOGGLE              digitalToggle(LED1_GPIO, LED1_PIN)
 #ifndef LED1_INVERTED
-#define LED1_OFF                 digitalHi(LED1_GPIO, LED1_PIN);
-#define LED1_ON                  digitalLo(LED1_GPIO, LED1_PIN);
+#define LED1_OFF                 digitalHi(LED1_GPIO, LED1_PIN)
+#define LED1_ON                  digitalLo(LED1_GPIO, LED1_PIN)
 #else
-#define LED1_OFF                 digitalLo(LED1_GPIO, LED1_PIN);
-#define LED1_ON                  digitalHi(LED1_GPIO, LED1_PIN);
+#define LED1_OFF                 digitalLo(LED1_GPIO, LED1_PIN)
+#define LED1_ON                  digitalHi(LED1_GPIO, LED1_PIN)
 #endif // inverted
 #else
-#define LED1_TOGGLE
-#define LED1_OFF
-#define LED1_ON
+#define LED1_TOGGLE              do {} while(0)
+#define LED1_OFF                 do {} while(0)
+#define LED1_ON                  do {} while(0)
 #endif
 
 
 #ifdef LED2
-#define LED2_TOGGLE              digitalToggle(LED2_GPIO, LED2_PIN);
+#define LED2_TOGGLE              digitalToggle(LED2_GPIO, LED2_PIN)
 #ifndef LED2_INVERTED
-#define LED2_OFF                 digitalHi(LED2_GPIO, LED2_PIN);
-#define LED2_ON                  digitalLo(LED2_GPIO, LED2_PIN);
+#define LED2_OFF                 digitalHi(LED2_GPIO, LED2_PIN)
+#define LED2_ON                  digitalLo(LED2_GPIO, LED2_PIN)
 #else
-#define LED2_OFF                 digitalLo(LED2_GPIO, LED2_PIN);
-#define LED2_ON                  digitalHi(LED2_GPIO, LED2_PIN);
+#define LED2_OFF                 digitalLo(LED2_GPIO, LED2_PIN)
+#define LED2_ON                  digitalHi(LED2_GPIO, LED2_PIN)
 #endif // inverted
 #else
-#define LED2_TOGGLE
-#define LED2_OFF
-#define LED2_ON
+#define LED2_TOGGLE              do {} while(0)
+#define LED2_OFF                 do {} while(0)
+#define LED2_ON                  do {} while(0)
 #endif
 
 void ledInit(void);
diff --git a/src/main/drivers/pwm_mapping.c b/src/main/drivers/pwm_mapping.c
index 6ac1e7847..533d98074 100644
--- a/src/main/drivers/pwm_mapping.c
+++ b/src/main/drivers/pwm_mapping.c
@@ -351,13 +351,10 @@ pwmOutputConfiguration_t *pwmInit(drv_pwm_config_t *init)
 
     setup = hardwareMaps[i];
 
-    for (i = 0; i < USABLE_TIMER_CHANNEL_COUNT; i++) {
+    for (i = 0; i < USABLE_TIMER_CHANNEL_COUNT && setup[i] != 0xFFFF; i++) {
         uint8_t timerIndex = setup[i] & 0x00FF;
         uint8_t type = (setup[i] & 0xFF00) >> 8;
 
-        if (setup[i] == 0xFFFF) // terminator
-            break;
-
         const timerHardware_t *timerHardwarePtr = &timerHardware[timerIndex];
 
 #ifdef OLIMEXINO_UNCUT_LED2_E_JUMPER
diff --git a/src/main/drivers/serial_uart.c b/src/main/drivers/serial_uart.c
index 0057b7ba9..90b7648f3 100644
--- a/src/main/drivers/serial_uart.c
+++ b/src/main/drivers/serial_uart.c
@@ -34,10 +34,7 @@
 
 #include "serial.h"
 #include "serial_uart.h"
-
-uartPort_t *serialUSART1(uint32_t baudRate, portMode_t mode);
-uartPort_t *serialUSART2(uint32_t baudRate, portMode_t mode);
-uartPort_t *serialUSART3(uint32_t baudRate, portMode_t mode);
+#include "serial_uart_impl.h"
 
 static void usartConfigurePinInversion(uartPort_t *uartPort) {
 #if !defined(INVERTER) && !defined(STM32F303xC)
diff --git a/src/main/drivers/serial_uart.h b/src/main/drivers/serial_uart.h
index 817929f28..6a7357d26 100644
--- a/src/main/drivers/serial_uart.h
+++ b/src/main/drivers/serial_uart.h
@@ -44,8 +44,6 @@ typedef struct {
     USART_TypeDef *USARTx;
 } uartPort_t;
 
-extern const struct serialPortVTable uartVTable[];
-
 serialPort_t *uartOpen(USART_TypeDef *USARTx, serialReceiveCallbackPtr callback, uint32_t baudRate, portMode_t mode, serialInversion_e inversion);
 
 // serialPort API
diff --git a/src/main/drivers/serial_uart_impl.h b/src/main/drivers/serial_uart_impl.h
new file mode 100644
index 000000000..713405bc0
--- /dev/null
+++ b/src/main/drivers/serial_uart_impl.h
@@ -0,0 +1,29 @@
+/*
+ * This file is part of Cleanflight.
+ *
+ * Cleanflight is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Cleanflight is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+// device specific uart implementation is defined here
+
+extern const struct serialPortVTable uartVTable[];
+
+void uartStartTxDMA(uartPort_t *s);
+
+uartPort_t *serialUSART1(uint32_t baudRate, portMode_t mode);
+uartPort_t *serialUSART2(uint32_t baudRate, portMode_t mode);
+uartPort_t *serialUSART3(uint32_t baudRate, portMode_t mode);
+
diff --git a/src/main/drivers/serial_uart_stm32f10x.c b/src/main/drivers/serial_uart_stm32f10x.c
index 5369206dc..02a99b3f6 100644
--- a/src/main/drivers/serial_uart_stm32f10x.c
+++ b/src/main/drivers/serial_uart_stm32f10x.c
@@ -34,6 +34,7 @@
 
 #include "serial.h"
 #include "serial_uart.h"
+#include "serial_uart_impl.h"
 
 #ifdef USE_USART1
 static uartPort_t uartPort1;
@@ -54,8 +55,6 @@ static uartPort_t uartPort3;
 #undef USE_USART1_RX_DMA
 #endif
 
-void uartStartTxDMA(uartPort_t *s);
-
 void usartIrqCallback(uartPort_t *s)
 {
     uint16_t SR = s->USARTx->SR;
diff --git a/src/main/drivers/serial_uart_stm32f30x.c b/src/main/drivers/serial_uart_stm32f30x.c
index f7bc087e0..6565e27fb 100644
--- a/src/main/drivers/serial_uart_stm32f30x.c
+++ b/src/main/drivers/serial_uart_stm32f30x.c
@@ -35,6 +35,7 @@
 
 #include "serial.h"
 #include "serial_uart.h"
+#include "serial_uart_impl.h"
 
 // Using RX DMA disables the use of receive callbacks
 #define USE_USART1_RX_DMA
@@ -70,12 +71,17 @@
 #define UART3_RX_PINSOURCE  GPIO_PinSource11
 #endif
 
+#ifdef USE_USART1
 static uartPort_t uartPort1;
+#endif
+#ifdef USE_USART2
 static uartPort_t uartPort2;
+#endif
+#ifdef USE_USART3
 static uartPort_t uartPort3;
+#endif
 
-void uartStartTxDMA(uartPort_t *s);
-
+#ifdef USE_USART1
 uartPort_t *serialUSART1(uint32_t baudRate, portMode_t mode)
 {
     uartPort_t *s;
@@ -148,7 +154,9 @@ uartPort_t *serialUSART1(uint32_t baudRate, portMode_t mode)
 
     return s;
 }
+#endif
 
+#ifdef USE_USART2
 uartPort_t *serialUSART2(uint32_t baudRate, portMode_t mode)
 {
     uartPort_t *s;
@@ -227,7 +235,9 @@ uartPort_t *serialUSART2(uint32_t baudRate, portMode_t mode)
 
     return s;
 }
+#endif
 
+#ifdef USE_USART3
 uartPort_t *serialUSART3(uint32_t baudRate, portMode_t mode)
 {
     uartPort_t *s;
@@ -306,6 +316,7 @@ uartPort_t *serialUSART3(uint32_t baudRate, portMode_t mode)
 
     return s;
 }
+#endif
 
 static void handleUsartTxDma(uartPort_t *s)
 {
@@ -338,7 +349,7 @@ void DMA1_Channel7_IRQHandler(void)
 #endif
 
 // USART3 Tx DMA Handler
-#ifdef USE_USART2_TX_DMA
+#ifdef USE_USART3_TX_DMA
 void DMA1_Channel2_IRQHandler(void)
 {
     uartPort_t *s = &uartPort3;
@@ -381,24 +392,29 @@ void usartIrqHandler(uartPort_t *s)
     }
 }
 
+#ifdef USE_USART1
 void USART1_IRQHandler(void)
 {
     uartPort_t *s = &uartPort1;
 
     usartIrqHandler(s);
 }
+#endif
 
+#ifdef USE_USART2
 void USART2_IRQHandler(void)
 {
     uartPort_t *s = &uartPort2;
 
     usartIrqHandler(s);
 }
+#endif
 
+#ifdef USE_USART3
 void USART3_IRQHandler(void)
 {
     uartPort_t *s = &uartPort3;
 
     usartIrqHandler(s);
 }
-
+#endif
diff --git a/src/main/drivers/system.c b/src/main/drivers/system.c
index d5a4860fd..2de34f307 100644
--- a/src/main/drivers/system.c
+++ b/src/main/drivers/system.c
@@ -31,7 +31,7 @@
 #include "system.h"
 
 // cycles per microsecond
-static volatile uint32_t usTicks = 0;
+static uint32_t usTicks = 0;
 // current uptime for 1kHz systick timer. will rollover after 49 days. hopefully we won't care.
 static volatile uint32_t sysTickUptime = 0;
 
diff --git a/src/main/io/serial_cli.c b/src/main/io/serial_cli.c
index fb9240095..e04b6187a 100644
--- a/src/main/io/serial_cli.c
+++ b/src/main/io/serial_cli.c
@@ -1448,16 +1448,16 @@ static void cliSetVar(const clivalue_t *var, const int_float_value_t value)
     switch (var->type & VALUE_TYPE_MASK) {
         case VAR_UINT8:
         case VAR_INT8:
-            *(char *)ptr = (char)value.int_value;
+            *(int8_t *)ptr = value.int_value;
             break;
 
         case VAR_UINT16:
         case VAR_INT16:
-            *(short *)ptr = (short)value.int_value;
+            *(int16_t *)ptr = value.int_value;
             break;
 
         case VAR_UINT32:
-            *(int *)ptr = (int)value.int_value;
+            *(uint32_t *)ptr = value.int_value;
             break;
 
         case VAR_FLOAT:
@@ -1650,7 +1650,7 @@ void cliProcess()
             }
             for (; i < bufferIndex; i++)
                 cliWrite(cliBuffer[i]);
-        } else if (!bufferIndex && c == 4) {
+        } else if (!bufferIndex && c == 4) {   // CTRL-D
             cliExit(cliBuffer);
             return;
         } else if (c == 12) {
diff --git a/src/main/main.c b/src/main/main.c
index 80c04eb3c..8fbe3e663 100644
--- a/src/main/main.c
+++ b/src/main/main.c
@@ -175,7 +175,7 @@ void init(void)
 
     ledInit();
 
-    #ifdef SPEKTRUM_BIND
+#ifdef SPEKTRUM_BIND
     if (feature(FEATURE_RX_SERIAL)) {
         switch (masterConfig.rxConfig.serialrx_provider) {
             case SERIALRX_SPEKTRUM1024:
diff --git a/src/main/sensors/battery.c b/src/main/sensors/battery.c
index a367cb8f8..83fb29d82 100644
--- a/src/main/sensors/battery.c
+++ b/src/main/sensors/battery.c
@@ -92,23 +92,20 @@ void batteryInit(batteryConfig_t *initialBatteryConfig)
         delay((32 / BATTERY_SAMPLE_COUNT) * 10);
     }
 
-    // autodetect cell count, going from 1S..8S
-    for (i = 1; i < 8; i++) {
-        if (vbat < i * batteryConfig->vbatmaxcellvoltage)
-            break;
-    }
-
-    batteryCellCount = i;
+    unsigned cells = (vbat / batteryConfig->vbatmaxcellvoltage) + 1;
+    if(cells > 8)            // something is wrong, we expect 8 cells maximum (and autodetection will be problematic at 6+ cells)
+        cells = 8;
+    batteryCellCount = cells;
     batteryWarningVoltage = batteryCellCount * batteryConfig->vbatwarningcellvoltage;
     batteryCriticalVoltage = batteryCellCount * batteryConfig->vbatmincellvoltage;
 }
 
-#define ADCVREF 33L
+#define ADCVREF 3300   // in mV
 int32_t currentSensorToCentiamps(uint16_t src)
 {
     int32_t millivolts;
 
-    millivolts = ((uint32_t)src * ADCVREF * 100) / 4095;
+    millivolts = ((uint32_t)src * ADCVREF) / 4096;
     millivolts -= batteryConfig->currentMeterOffset;
 
     return (millivolts * 1000) / (int32_t)batteryConfig->currentMeterScale; // current in 0.01A steps
diff --git a/src/main/telemetry/frsky.c b/src/main/telemetry/frsky.c
index c61cb87f5..9c63ffd9b 100644
--- a/src/main/telemetry/frsky.c
+++ b/src/main/telemetry/frsky.c
@@ -177,6 +177,7 @@ static void sendBaro(void)
     serialize16(ABS(BaroAlt % 100));
 }
 
+#ifdef GPS
 static void sendGpsAltitude(void)
 {
     uint16_t altitude = GPS_altitude;
@@ -189,7 +190,7 @@ static void sendGpsAltitude(void)
     sendDataHead(ID_GPS_ALTIDUTE_AP);
     serialize16(0);
 }
-
+#endif
 
 static void sendThrottleOrBatterySizeAsRpm(void)
 {
@@ -212,6 +213,7 @@ static void sendTemperature1(void)
 #endif
 }
 
+#ifdef GPS
 static void sendSatalliteSignalQualityAsTemperature2(void)
 {
     uint16_t satellite = GPS_numSat;
@@ -241,6 +243,7 @@ static void sendSpeed(void)
     sendDataHead(ID_GPS_SPEED_AP);
     serialize16(0); //Not dipslayed
 }
+#endif
 
 static void sendTime(void)
 {
diff --git a/src/main/telemetry/hott.c b/src/main/telemetry/hott.c
index eb29cbd7a..87e2f21df 100644
--- a/src/main/telemetry/hott.c
+++ b/src/main/telemetry/hott.c
@@ -220,15 +220,15 @@ static inline void hottEAMUpdateBattery(HOTT_EAM_MSG_t *hottEAMMessage)
 
 static inline void hottEAMUpdateCurrentMeter(HOTT_EAM_MSG_t *hottEAMMessage)
 {
-	int32_t amp = amperage / 10;
-	hottEAMMessage->current_L = amp & 0xFF;
+    int32_t amp = amperage / 10;
+    hottEAMMessage->current_L = amp & 0xFF;
     hottEAMMessage->current_H = amp >> 8;
 }
 
 static inline void hottEAMUpdateBatteryDrawnCapacity(HOTT_EAM_MSG_t *hottEAMMessage)
 {
-	int32_t mAh = mAhDrawn / 10;
-	hottEAMMessage->batt_cap_L = mAh & 0xFF;
+    int32_t mAh = mAhDrawn / 10;
+    hottEAMMessage->batt_cap_L = mAh & 0xFF;
     hottEAMMessage->batt_cap_H = mAh >> 8;
 }
 
diff --git a/src/main/telemetry/smartport.c b/src/main/telemetry/smartport.c
index 6f74e55a1..58d855645 100644
--- a/src/main/telemetry/smartport.c
+++ b/src/main/telemetry/smartport.c
@@ -304,17 +304,18 @@ void handleSmartPortTelemetry(void)
         smartPortIdCnt++;
 
         int32_t tmpi;
-        uint32_t tmpui;
         static uint8_t t1Cnt = 0;
 
         switch(id) {
+#ifdef GPS
             case FSSP_DATAID_SPEED      :
                 if (sensors(SENSOR_GPS) && STATE(GPS_FIX)) {
-                    tmpui = (GPS_speed * 36 + 36 / 2) / 100;
+                    uint32_t tmpui = (GPS_speed * 36 + 36 / 2) / 100;
                     smartPortSendPackage(id, tmpui); // given in 0.1 m/s, provide in KM/H
                     smartPortHasRequest = 0;
                 }
                 break;
+#endif
             case FSSP_DATAID_VFAS       :
                 smartPortSendPackage(id, vbat * 83); // supposedly given in 0.1V, unknown requested unit
                 // multiplying by 83 seems to make Taranis read correctly
@@ -335,9 +336,10 @@ void handleSmartPortTelemetry(void)
                 break;
             //case FSSP_DATAID_ADC1       :
             //case FSSP_DATAID_ADC2       :
+#ifdef GPS
             case FSSP_DATAID_LATLONG    :
                 if (sensors(SENSOR_GPS) && STATE(GPS_FIX)) {
-                    tmpui = 0;
+                    uint32_t tmpui = 0;
                     // the same ID is sent twice, one for longitude, one for latitude
                     // the MSB of the sent uint32_t helps FrSky keep track
                     // the even/odd bit of our counter helps us keep track
@@ -360,6 +362,7 @@ void handleSmartPortTelemetry(void)
                     smartPortHasRequest = 0;
                 }
                 break;
+#endif
             //case FSSP_DATAID_CAP_USED   :
             case FSSP_DATAID_VARIO      :
                 smartPortSendPackage(id, vario); // unknown given unit but requested in 100 = 1m/s
@@ -431,21 +434,25 @@ void handleSmartPortTelemetry(void)
                 break;
             case FSSP_DATAID_T2         :
                 if (sensors(SENSOR_GPS)) {
+#ifdef GPS
                     // provide GPS lock status
                     smartPortSendPackage(id, (STATE(GPS_FIX) ? 1000 : 0) + (STATE(GPS_FIX_HOME) ? 2000 : 0) + GPS_numSat);
                     smartPortHasRequest = 0;
+#endif
                 }
                 else {
                     smartPortSendPackage(id, 0);
                     smartPortHasRequest = 0;
                 }
                 break;
+#ifdef GPS
             case FSSP_DATAID_GPS_ALT    :
                 if (sensors(SENSOR_GPS) && STATE(GPS_FIX)) {
                     smartPortSendPackage(id, GPS_altitude * 1000); // given in 0.1m , requested in 100 = 1m
                     smartPortHasRequest = 0;
                 }
                 break;
+#endif
             default:
                 break;
                 // if nothing is sent, smartPortHasRequest isn't cleared, we already incremented the counter, just wait for the next loop
diff --git a/src/test/unit/battery_unittest.cc b/src/test/unit/battery_unittest.cc
index 2a6701743..8eccb32e5 100644
--- a/src/test/unit/battery_unittest.cc
+++ b/src/test/unit/battery_unittest.cc
@@ -37,7 +37,17 @@ TEST(BatteryTest, BatteryADCToVoltage)
 {
     // given
 
-    batteryConfig_t batteryConfig;
+    batteryConfig_t batteryConfig = {
+        .vbatscale = 110,
+        .vbatmaxcellvoltage = 43,
+        .vbatmincellvoltage = 33,
+        .vbatwarningcellvoltage = 35,
+        .currentMeterScale = 400,
+        .currentMeterOffset = 0,
+        .currentMeterType = CURRENT_SENSOR_NONE,
+        .multiwiiCurrentMeterOutput = 0,
+        .batteryCapacity = 2200,
+    };
 
     // batteryInit() reads a bunch of fields including vbatscale, so set up the config with useful initial values:
     memset(&batteryConfig, 0, sizeof(batteryConfig));