diff --git a/mxgrub/mxgrub b/mxgrub/mxgrub
index 0b26ad5..3b36fa0 100755
--- a/mxgrub/mxgrub
+++ b/mxgrub/mxgrub
@@ -359,7 +359,7 @@ sub build_microcode {
 set -e
 DSTDIR=kernel/x86/microcode
 mkdir -p /scratch/local/mxgrub-build-microcode/
-cd $_
+cd \$_
 mkdir -p "\$DSTDIR"
 cat $pattern > "\$DSTDIR"/$binname
 find . | cpio -o -H newc > $image