diff --git a/src/main/drivers/serial_uart_stm32f4xx.c b/src/main/drivers/serial_uart_stm32f4xx.c
index f79a99ae6e..d6bd58024e 100644
--- a/src/main/drivers/serial_uart_stm32f4xx.c
+++ b/src/main/drivers/serial_uart_stm32f4xx.c
@@ -30,8 +30,8 @@
 #include "serial_uart.h"
 #include "serial_uart_impl.h"
 
-#define UART_RX_BUFFER_SIZE UART1_RX_BUFFER_SIZE
-#define UART_TX_BUFFER_SIZE UART1_TX_BUFFER_SIZE
+#define UART_RX_BUFFER_SIZE 512
+#define UART_TX_BUFFER_SIZE 512
 
 typedef enum UARTDevice {
     UARTDEV_1 = 0,
diff --git a/src/main/io/serial_4way_avrootloader.c b/src/main/io/serial_4way_avrootloader.c
index 26621df4bb..4ccea1601a 100644
--- a/src/main/io/serial_4way_avrootloader.c
+++ b/src/main/io/serial_4way_avrootloader.c
@@ -330,7 +330,8 @@ uint8_t BL_WriteFlash(ioMem_t *pMem)
     return BL_WriteA(CMD_PROG_FLASH, pMem, (40 / START_BIT_TIMEOUT_MS));
 }
 
-#else
+#endif
+#if defined(USE_SERIAL_4WAY_BLHELI_BOOTLOADER) && defined(USE_FAKE_ESC)
 
 #define FAKE_PAGE_SIZE 512
 #define FAKE_FLASH_SIZE 16385