diff --git a/types/wlr_screenshooter.c b/types/wlr_screenshooter.c
index b16c1ba9..ddcaf52b 100644
--- a/types/wlr_screenshooter.c
+++ b/types/wlr_screenshooter.c
@@ -7,7 +7,7 @@
 #include <wlr/util/log.h>
 #include "screenshooter-protocol.h"
 
-static void copy_bgra_yflip(uint8_t *dst, uint8_t *src, int32_t height,
+static void copy_yflip(uint8_t *dst, uint8_t *src, int32_t height,
 		int32_t stride) {
 	uint8_t *end = dst + height * stride;
 	while (dst < end) {
@@ -34,7 +34,7 @@ static void output_frame_notify(struct wl_listener *listener, void *_data) {
 
 	void *data = wl_shm_buffer_get_data(state->shm_buffer);
 	wl_shm_buffer_begin_access(state->shm_buffer);
-	copy_bgra_yflip(data, state->pixels + state->stride * (state->height - 1),
+	copy_yflip(data, state->pixels + state->stride * (state->height - 1),
 		state->height, state->stride);
 	wl_shm_buffer_end_access(state->shm_buffer);
 
@@ -63,6 +63,12 @@ static void screenshooter_shoot(struct wl_client *client,
 		return;
 	}
 
+	uint32_t format = wl_shm_buffer_get_format(shm_buffer);
+	if (format != WL_SHM_FORMAT_XRGB8888) {
+		wlr_log(L_ERROR, "Invalid buffer: unsupported format");
+		return;
+	}
+
 	uint8_t *pixels = malloc(stride * height);
 	if (pixels == NULL) {
 		wl_client_post_no_memory(client);