Grub 2 os prober for windows 8

I'm trying to dual boot with fedora 20 and windows 8. I install first windows and then fedora. And grub detects windows automatically. So the default \etc\grub.d\30_os-prober for windows is this: case ${BOOT} in chain) onstr="$(gettext_printf "(on %s)" "${DEVICE}")" cat << EOF menuentry '$(echo "${LONGNAME} $onstr" | grub_quote)' --class windows --class os \$menuentry_id_option 'osprober-chain-$(grub_get_device_id "${DEVICE}")' { EOF save_default_entry | grub_add_tab prepare_grub_to_access_device ${DEVICE} | grub_add_tab case ${LONGNAME} in Windows\ Vista*|Windows\ 7*|Windows\ Server\ 2008*) ;; *) cat << EOF drivemap -s (hd0) \${root} EOF ;; esac cat <menuentry which doesn't boot windows: **What I've tried** I created in my /etc/grub.d/40_custom manually a menuentry which works fine menuentry "Windows" { insmod part_gpt insmod fat insmod search_fs_uuid insmod chain search --fs-uuid --no-floppy --set=root your_UUID chainloader (${root})/efi/Microsoft/Boot/bootmgfw.efi } So I try to adapt this for the \etc\grub.d\30_os-prober and add replace the last part with this: cat <