diff --git a/manifests/tftp.pp b/manifests/tftp.pp
index 740537d2..48437077 100644
--- a/manifests/tftp.pp
+++ b/manifests/tftp.pp
@@ -32,8 +32,8 @@
     }
     'Debian': {
       $grub_type = 'debian'
-      # taken from https://anonscm.debian.org/cgit/pkg-grub/grub.git/tree/debian/build-efi-images
-      $grub_modules = 'all_video boot btrfs cat chain configfile echo efifwsetup efinet ext2 fat font gettext gfxmenu gfxterm gfxterm_background gzio halt hfsplus iso9660 jpeg keystatus loadenv linux lsefi lsefimmap lsefisystab lssal memdisk minicmd normal part_apple part_msdos part_gpt password_pbkdf2 png reboot search search_fs_uuid search_fs_file search_label sleep test true video zfs zfscrypt zfsinfo linuxefi lvm mdraid09 mdraid1x raid5rec raid6rec tftp'
+      # taken from https://anonscm.debian.org/cgit/pkg-grub/grub.git/tree/debian/build-efi-images + regexp
+      $grub_modules = 'all_video boot btrfs cat chain configfile echo efifwsetup efinet ext2 fat font gettext gfxmenu gfxterm gfxterm_background gzio halt hfsplus iso9660 jpeg keystatus loadenv linux lsefi lsefimmap lsefisystab lssal memdisk minicmd normal part_apple part_msdos part_gpt password_pbkdf2 png reboot search search_fs_uuid search_fs_file search_label sleep test true video zfs zfscrypt zfsinfo linuxefi lvm mdraid09 mdraid1x raid5rec raid6rec tftp regexp'
     }
     default: {
       warning("Unable to detect EFI loader for OS family '${::osfamily}'")
@@ -97,7 +97,7 @@
 
       exec {'build-grub2-efi-image':
         command => "/usr/bin/grub-mkimage -O x86_64-efi -d ${efi_dir} -o ${foreman_proxy::tftp_root}/grub2/grubx64.efi -p '' ${grub_modules}",
-        creates => "${foreman_proxy::tftp_root}/grub2/grubx64.efi",
+        unless  => "/bin/grep -q regexp '${foreman_proxy::tftp_root}/grub2/grubx64.efi'",
         require => [File[$foreman_proxy::tftp_dirs], Package['grub-common','grub-efi-amd64-bin']],
       } ->
       file {"${foreman_proxy::tftp_root}/grub2/grubx64.efi":
diff --git a/spec/classes/foreman_proxy__config__spec.rb b/spec/classes/foreman_proxy__config__spec.rb
index 44ded20b..8cce6b75 100644
--- a/spec/classes/foreman_proxy__config__spec.rb
+++ b/spec/classes/foreman_proxy__config__spec.rb
@@ -301,7 +301,7 @@
 
           it 'should generate efi image from grub2 modules for Debian' do
             should contain_exec('build-grub2-efi-image').
-              with_creates("#{tftp_root}/grub2/grubx64.efi")
+              with_unless("/bin/grep -q regexp '#{tftp_root}/grub2/grubx64.efi'")
             should contain_file("#{tftp_root}/grub2/grubx64.efi").
               with_mode('0644').
               with_owner('root').
diff --git a/templates/grub.cfg.erb b/templates/grub.cfg.erb
new file mode 100644
index 00000000..3686779a
--- /dev/null
+++ b/templates/grub.cfg.erb
@@ -0,0 +1,8 @@
+insmod regexp
+
+set net_pxe_mac=$net_default_mac
+regexp --set=1:m1 --set=2:m2 --set=3:m3 --set=4:m4 --set=5:m5 --set=6:m6 '^([0-9a-f]{1,2})\:([0-9a-f]{1,2})\:([0-9a-f]{1,2})\:([0-9a-f]{1,2})\:([0-9a-f]{1,2})\:([0-9a-f]{1,2})' "$net_default_mac"
+mac_dashed=${m1}-${m2}-${m3}-${m4}-${m5}-${m6}
+
+mac_configfile=$prefix/grub.cfg-01-$mac_dashed
+source "$mac_configfile"