diff --git a/extmod/modtrezorui/display.c b/extmod/modtrezorui/display.c
index 0fca555186..67773170bd 100644
--- a/extmod/modtrezorui/display.c
+++ b/extmod/modtrezorui/display.c
@@ -413,7 +413,9 @@ void display_raw(uint8_t reg, const uint8_t *data, int datalen)
     if (reg) {
         CMD(reg);
     }
-    DATAS(data, datalen);
+    if (data && datalen > 0) {
+        DATAS(data, datalen);
+    }
 }
 
 int *display_offset(int xy[2])
diff --git a/extmod/modtrezorui/modtrezorui-display.h b/extmod/modtrezorui/modtrezorui-display.h
index b1388ba7f8..669a49af23 100644
--- a/extmod/modtrezorui/modtrezorui-display.h
+++ b/extmod/modtrezorui/modtrezorui-display.h
@@ -337,18 +337,22 @@ STATIC mp_obj_t mod_TrezorUi_Display_offset(size_t n_args, const mp_obj_t *args)
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_TrezorUi_Display_offset_obj, 1, 2, mod_TrezorUi_Display_offset);
 
-/// def trezor.ui.display.raw(reg: int, data: bytes) -> None:
+/// def trezor.ui.display.raw(reg: int, data: bytes=None) -> None:
 ///     '''
 ///     Performs a raw command on the display. Read the datasheet to learn more.
 ///     '''
-STATIC mp_obj_t mod_TrezorUi_Display_raw(mp_obj_t self, mp_obj_t reg, mp_obj_t data) {
-    mp_int_t r = mp_obj_get_int(reg);
-    mp_buffer_info_t raw;
-    mp_get_buffer_raise(data, &raw, MP_BUFFER_READ);
-    display_raw(r, (raw.len > 0) ? raw.buf : "" , raw.len);
+STATIC mp_obj_t mod_TrezorUi_Display_raw(size_t n_args, const mp_obj_t *args) {
+    mp_int_t r = mp_obj_get_int(args[1]);
+    if (n_args > 2){
+        mp_buffer_info_t raw;
+        mp_get_buffer_raise(args[2], &raw, MP_BUFFER_READ);
+        display_raw(r, raw.buf, raw.len);
+    } else {
+        display_raw(r, NULL, 0);
+    }
     return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_3(mod_TrezorUi_Display_raw_obj, mod_TrezorUi_Display_raw);
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_TrezorUi_Display_raw_obj, 2, 3, mod_TrezorUi_Display_raw);
 
 /// def trezor.ui.display.save(filename: string) -> None:
 ///     '''