diff --git a/src/platforms/common/aux_serial.c b/src/platforms/common/aux_serial.c
index c8290a9..c27675f 100644
--- a/src/platforms/common/aux_serial.c
+++ b/src/platforms/common/aux_serial.c
@@ -23,6 +23,7 @@
 #include <libopencm3/stm32/usart.h>
 #include <libopencm3/stm32/dma.h>
 #elif defined(LM4F)
+#include <libopencm3/lm4f/rcc.h>
 #include <libopencm3/lm4f/uart.h>
 #else
 #error "Unknown processor target"
@@ -36,6 +37,11 @@
 #include "usb.h"
 #include "aux_serial.h"
 
+/* Fifo in pointer, writes assumed to be atomic, should be only incremented within RX ISR */
+uint8_t buf_rx_in;
+/* Fifo out pointer, writes assumed to be atomic, should be only incremented outside RX ISR */
+uint8_t buf_rx_out;
+
 #if defined(STM32F0) || defined(STM32F1) || defined(STM32F3) || defined(STM32F4)
 static char aux_serial_transmit_buffer[2U][AUX_UART_BUFFER_SIZE];
 static uint8_t aux_serial_transmit_buffer_index;
diff --git a/src/platforms/common/usbuart.h b/src/platforms/common/usbuart.h
index 06fe115..ce22761 100644
--- a/src/platforms/common/usbuart.h
+++ b/src/platforms/common/usbuart.h
@@ -42,8 +42,6 @@ void debug_uart_run(void);
 
 /* RX Fifo buffer with space for copy fn overrun */
 extern char buf_rx[AUX_UART_BUFFER_SIZE + sizeof(uint64_t)];
-/* RX Fifo out pointer, writes assumed to be atomic */
-extern uint8_t buf_rx_out;
 
 #ifdef ENABLE_DEBUG
 /* Debug Fifo buffer with space for copy fn overrun */
@@ -58,10 +56,8 @@ extern uint8_t usb_dbg_out;
 
 /* RX Fifo buffer */
 extern char buf_rx[AUX_UART_BUFFER_SIZE];
-/* Fifo in pointer, writes assumed to be atomic, should be only incremented within RX ISR */
-extern uint8_t buf_rx_in;
-/* Fifo out pointer, writes assumed to be atomic, should be only incremented outside RX ISR */
-extern uint8_t buf_rx_out;
 #endif
 
+extern uint8_t buf_rx_out;
+
 #endif
diff --git a/src/platforms/stm32/usbuart.c b/src/platforms/stm32/usbuart.c
index 13ee742..32d8e7e 100644
--- a/src/platforms/stm32/usbuart.c
+++ b/src/platforms/stm32/usbuart.c
@@ -40,8 +40,6 @@
 
 /* RX Fifo buffer with space for copy fn overrun */
 char buf_rx[AUX_UART_BUFFER_SIZE + sizeof(uint64_t)];
-/* RX Fifo out pointer, writes assumed to be atomic */
-uint8_t buf_rx_out;
 
 #ifdef ENABLE_DEBUG
 /* Debug Fifo buffer with space for copy fn overrun */
diff --git a/src/platforms/tm4c/usbuart.c b/src/platforms/tm4c/usbuart.c
index 94db5d4..919821c 100644
--- a/src/platforms/tm4c/usbuart.c
+++ b/src/platforms/tm4c/usbuart.c
@@ -24,7 +24,6 @@
 #include <libopencm3/cm3/scs.h>
 #include <libopencm3/usb/usbd.h>
 #include <libopencm3/usb/cdc.h>
-#include <libopencm3/lm4f/rcc.h>
 #include <libopencm3/lm4f/uart.h>
 
 #include "general.h"
@@ -32,7 +31,3 @@
 
 /* RX Fifo buffer */
 char buf_rx[AUX_UART_BUFFER_SIZE];
-/* Fifo in pointer, writes assumed to be atomic, should be only incremented within RX ISR */
-uint8_t buf_rx_in;
-/* Fifo out pointer, writes assumed to be atomic, should be only incremented outside RX ISR */
-uint8_t buf_rx_out;