diff --git a/hw/application_fpga/tools/b2s/b2s.go b/hw/application_fpga/tools/b2s/b2s.go
index 083a366..2f5c3b9 100644
--- a/hw/application_fpga/tools/b2s/b2s.go
+++ b/hw/application_fpga/tools/b2s/b2s.go
@@ -45,7 +45,7 @@ func main() {
 
 	message, err := os.ReadFile(messageFile)
 	if err != nil {
-		fmt.Printf("%v\n", err)
+		fmt.Fprintf(os.Stderr, "%v\n", err)
 		os.Exit(1)
 	}