fix issue #516

Arch 2020.10.1 iso boot failed in UEFI mode.

INSTALL/grub/grub.cfg

@@ -496,6 +496,8 @@ function uefi_linux_menu_func {
             if [ -d (loop)/arch ]; then
                 if [ -f (loop)/arch/boot/x86_64/archiso.img ]; then
                     vt_add_replace_file $vtindex "EFI\\archiso\\archiso.img"
+                elif [ -f (loop)/arch/boot/x86_64/initramfs-linux.img ]; then
+                    vt_add_replace_file $vtindex "arch\\boot\\x86_64\\initramfs-linux.img"
                 elif [ -f (loop)/boot/initramfs_x86_64.img ]; then
                     vt_add_replace_file $vtindex "boot\\initramfs_x86_64.img"
                 fi