diff --git a/src/main/drivers/serial.h b/src/main/drivers/serial.h
index 773aaa74a6..288721ad6b 100644
--- a/src/main/drivers/serial.h
+++ b/src/main/drivers/serial.h
@@ -83,7 +83,7 @@ struct serialPortVTable {
 void serialWrite(serialPort_t *instance, uint8_t ch);
 uint8_t serialRxBytesWaiting(serialPort_t *instance);
 uint8_t serialTxBytesFree(serialPort_t *instance);
-void serialWriteBuf(serialPort_t *instance, void *data, int count);
+void serialWriteBuf(serialPort_t *instance, uint8_t *data, int count);
 uint8_t serialRead(serialPort_t *instance);
 void serialSetBaudRate(serialPort_t *instance, uint32_t baudRate);
 void serialSetMode(serialPort_t *instance, portMode_t mode);
@@ -92,6 +92,6 @@ void serialPrint(serialPort_t *instance, const char *str);
 uint32_t serialGetBaudRate(serialPort_t *instance);
 
 // A shim that adapts the bufWriter API to the serialWriteBuf() API.
-void serialWriteBufShim(void *instance, void *data, int count);
+void serialWriteBufShim(void *instance, uint8_t *data, int count);
 void serialBeginWrite(serialPort_t *instance);
 void serialEndWrite(serialPort_t *instance);