diff --git a/tools/mkboot b/tools/mkboot
index 98431b8b9..43f04f3cc 100755
--- a/tools/mkboot
+++ b/tools/mkboot
@@ -171,4 +171,5 @@ cdfdboot)
 	# copy image
 	dd if=$dev of=cdfdimage bs=8192 count=180
 esac
+sync
 exit 0