diff --git a/src/class/midi/midi_device.h b/src/class/midi/midi_device.h
index 6458a683c..10af21276 100644
--- a/src/class/midi/midi_device.h
+++ b/src/class/midi/midi_device.h
@@ -69,7 +69,7 @@ static inline bool     tud_midi_connected   (void);
 static inline uint32_t tud_midi_available   (void);
 static inline uint32_t tud_midi_read        (void* buffer, uint32_t bufsize);
 static inline void     tud_midi_read_flush  (void);
-static inline uint32_t tud_midi_write       (uint8_t jack_id, void const* buffer, uint32_t bufsize);
+static inline uint32_t tud_midi_write       (uint8_t jack_id, uint8_t const* buffer, uint32_t bufsize);
 static inline uint32_t tudi_midi_write24    (uint8_t jack_id, uint8_t b1, uint8_t b2, uint8_t b3);
 static inline bool     tud_midi_write_flush (void);
 
@@ -108,7 +108,7 @@ static inline void tud_midi_read_flush (void)
   tud_midi_n_read_flush(0, 0);
 }
 
-static inline uint32_t tud_midi_write (uint8_t jack_id, void const* buffer, uint32_t bufsize)
+static inline uint32_t tud_midi_write (uint8_t jack_id, uint8_t const* buffer, uint32_t bufsize)
 {
   return tud_midi_n_write(0, jack_id, buffer, bufsize);
 }