--- runtime/filetype.vim
+++ runtime/filetype.vim
@@ -146,7 +146,7 @@
 	\ endif
 
 " Grub (must be before catch *.lst)
-au BufNewFile,BufRead /boot/grub/menu.lst,/boot/grub/grub.conf,/etc/grub.conf	setf grub
+au BufNewFile,BufRead */boot/grub/menu.lst,*/boot/grub/grub.conf,*/etc/grub.conf	setf grub
 
 " Assembly (all kinds)
 " *.lst is not pure assembly, it has two extra columns (address, byte codes)