diff --git a/boot/grubfm/func.sh b/boot/grubfm/func.sh
index 2e10a078..57bd335c 100644
--- a/boot/grubfm/func.sh
+++ b/boot/grubfm/func.sh
@@ -19,6 +19,16 @@ function to_g4d_path {
   lua ${prefix}/g4d_path.lua;
 }
 
+function unmap_cd {
+  for dev in (cd*);
+  do
+    if [ -e ${dev} ];
+    then
+      map -x ${dev};
+    fi;
+  done;
+}
+
 regexp --set=1:grubfm_path '(/.*)$' "${grubfm_file}";
 regexp --set=1:grubfm_dir '^(.*/).*$' "${grubfm_path}";
 regexp --set=1:grubfm_device '^\(([0-9a-zA-Z,]+)\)/.*' "${grubfm_file}";
diff --git a/boot/grubfm/rules/iso/e2b.sh b/boot/grubfm/rules/iso/e2b.sh
index 25d53956..c02da2f6 100644
--- a/boot/grubfm/rules/iso/e2b.sh
+++ b/boot/grubfm/rules/iso/e2b.sh
@@ -22,6 +22,7 @@ then
   partnew --type=0x00 --file="${grubfm_file}" "${grubfm_disk}" 4;
   if [ "$grub_platform" = "efi" ];
   then
+    unmap_cd;
     map "${grubfm_file}";
   elif [ "$grub_platform" = "pc" ];
   then
diff --git a/boot/grubfm/rules/iso/map.sh b/boot/grubfm/rules/iso/map.sh
index f11ad331..b27cfc3f 100644
--- a/boot/grubfm/rules/iso/map.sh
+++ b/boot/grubfm/rules/iso/map.sh
@@ -2,6 +2,7 @@ source ${prefix}/func.sh;
 
 if [ "$grub_platform" = "efi" ];
 then
+  unmap_cd;
   map "${grubfm_file}";
 elif [ "$grub_platform" = "pc" ];
 then