diff --git a/vlib/builtin/builtin_nix.c.v b/vlib/builtin/builtin_nix.c.v
index c7dfb0d0d7..0e0cd6203f 100644
--- a/vlib/builtin/builtin_nix.c.v
+++ b/vlib/builtin/builtin_nix.c.v
@@ -100,7 +100,7 @@ fn print_backtrace_skipping_top_frames_linux(skipframes int) bool {
 					eprintln(sframe)
 					continue
 				}
-				buf := [1000]byte{}
+				buf := [1000]u8{}
 				mut output := ''
 				unsafe {
 					bp := &buf[0]