diff --git a/libr/io/p/io_gprobe.c b/libr/io/p/io_gprobe.c
index ae69141588..1f29399709 100644
--- a/libr/io/p/io_gprobe.c
+++ b/libr/io/p/io_gprobe.c
@@ -95,12 +95,11 @@ static ut8 gprobe_checksum_i2c (const ut8 *p, unsigned int size, ut8 initial) {
 static void gprobe_frame_i2c (RBuffer *frame) {
 	ut8 size = r_buf_size (frame) + 1;
 	ut8 header[] = {0x51, 0x80 + size + 3, 0xc2, 0x00, 0x00};
-	ut8 checksum;
 
 	r_buf_prepend_bytes (frame, &size, 1);
 	r_buf_prepend_bytes (frame, header, sizeof (header));
 
-	checksum = gprobe_checksum_i2c (r_buf_buffer (frame), r_buf_size (frame), GPROBE_I2C_ADDR);
+	ut8 checksum = gprobe_checksum_i2c (r_buf_buffer (frame), r_buf_size (frame), GPROBE_I2C_ADDR);
 
 	r_buf_append_bytes (frame, &checksum, 1);
 }
diff --git a/libr/util/buf.c b/libr/util/buf.c
index e55001dcbf..d9f2c3e257 100644
--- a/libr/util/buf.c
+++ b/libr/util/buf.c
@@ -402,7 +402,10 @@ R_API RBuffer *r_buf_new() {
 }
 
 R_API const ut8 *r_buf_buffer (RBuffer *b) {
-	return (b && !b->sparse)? b->buf: NULL;
+	if (b && !b->sparse && b->fd == -1 && !b->mmap) {
+		return b->buf;
+	}
+	r_return_val_if_fail (false, NULL);
 }
 
 R_API ut64 r_buf_size (RBuffer *b) {