This is Grub2 but it's edited so it can be used on tablets that doesn't have an "enter" key.
The "volume up" key functions as the "enter" key and the "volume down" functions as the "down" key. 
And after the pointer reaches the end of the list, it goes to the first entry. 
Now there is a delay (250ms) after every time menu cursor changes its position beacause volume keys originally move cursor too fast

These are the commands I used with grub-mkimage:
grub-mkimage -O x86_64-efi -o bootx64.efi -p "" --config=init.cfg part_gpt part_msdos ntfs ntfscomp hfsplus fat ext2 normal chain boot configfile linux multiboot ls cat echo configfile search search_fs_file search_fs_uuid search_label usb
grub-mkimage -O i386-efi -o bootia32.efi -p "" --config=init.cfg part_gpt part_msdos ntfs ntfscomp hfsplus fat ext2 normal chain boot configfile linux multiboot ls cat echo configfile search search_fs_file search_fs_uuid search_label usb