diff --git a/util/grub-mkrescue.in b/util/grub-mkrescue.in
index 4f151ac98..2ef9aa8bd 100644
--- a/util/grub-mkrescue.in
+++ b/util/grub-mkrescue.in
@@ -165,7 +165,7 @@ if test -e "${coreboot_dir}" ; then
     cat << EOF > ${memdisk_dir}/boot/grub/grub.cfg
 search --fs-uuid --set ${iso_uuid}
 set prefix=(\${root})/boot/grub/${target_cpu}-coreboot
-source $prefix/grub.cfg
+source \$prefix/grub.cfg
 EOF
     (for i in ${modules} ; do
         echo "insmod $i"
@@ -222,7 +222,7 @@ if test -e "${efi64_dir}" ; then
     cat << EOF > ${memdisk_dir}/boot/grub/grub.cfg
 search --fs-uuid --set ${iso_uuid}
 set prefix=(\${root})/boot/grub/${target_cpu}-efi
-source $prefix/grub.cfg
+source \$prefix/grub.cfg
 EOF
 
     tar -C ${memdisk_dir} -cf ${memdisk_img} boot