diff --git a/mxgrub/mxgrub b/mxgrub/mxgrub
index 527c143..3b36fa0 100755
--- a/mxgrub/mxgrub
+++ b/mxgrub/mxgrub
@@ -353,9 +353,23 @@ sub cmd_update {
 	update_grub_cfg();
 }
 
+sub build_microcode {
+    my ($pattern, $image, $binname) = @_;
+    sys(<<"EOF");
+set -e
+DSTDIR=kernel/x86/microcode
+mkdir -p /scratch/local/mxgrub-build-microcode/
+cd \$_
+mkdir -p "\$DSTDIR"
+cat $pattern > "\$DSTDIR"/$binname
+find . | cpio -o -H newc > $image
+rm -rf /scratch/local/mxgrub-build-microcode/
+EOF
+}
+
 sub cmd_initramfs {
-	sys('bash','-c','TMPDIR=/scratch/local DSTDIR="$TMPDIR/kernel/x86/microcode"; mkdir -p "$DSTDIR"; cd "$DSTDIR" ; cat /lib/firmware/amd-ucode/microcode_amd*.bin > $DSTDIR/AuthenticAMD.bin ; find . | cpio -o -H newc > /boot/amd-ucode.img ; rm -rf "$TMPDIR/kernel"');
-	sys('bash','-c','TMPDIR=/scratch/local DSTDIR="$TMPDIR/kernel/x86/microcode"; mkdir -p "$DSTDIR"; cd "$DSTDIR" ; cat /lib/firmware/intel-ucode/* > $DSTDIR/GenuineIntel.bin ; find . | cpio -o -H newc > /boot/intel-ucode.img ; rm -rf "$TMPDIR/kernel"');
+	build_microcode('/lib/firmware/amd-ucode/microcode_amd*.bin', '/boot/amd-ucode.img',  'AuthenticAMD.bin');
+	build_microcode('/lib/firmware/intel-ucode/*', '/boot/intel-ucode.img',  'GenuineIntel.bin');
 	sys('bash','-c','cd /project/admin/initramfs ; find . -name ".git*" -prune -or -print | cpio -H newc -o | gzip > /boot/grub/initramfs.igz');
 }