diff --git a/arch/sandbox/cpu/os.c b/arch/sandbox/cpu/os.c
index d4d6d78..1d87a53 100644
--- a/arch/sandbox/cpu/os.c
+++ b/arch/sandbox/cpu/os.c
@@ -85,6 +85,8 @@
 
 	if (os_flags & OS_O_CREAT)
 		flags |= O_CREAT;
+	if (os_flags & OS_O_TRUNC)
+		flags |= O_TRUNC;
 
 	return open(pathname, flags, 0777);
 }