UPA1AM18 update - emmc boot option disappeared

I had a functional copy of arch running on my board, updated the bios to UPA1AM18 and noticed a warning that the file to be written was larger than the flash area to be written to. I am no longer granted the option to boot from my emmc disk when clicking f7 at boot. Thoughts?
Comments
Unfortunately by default the BIOS only recognises Windows or Ubuntu.
You can either reinstall the OS or try to boot from the EFI shell, looking for the bootx64.efi binary in your /efi/boot folder
And then run this command as root:
$ grub-install --removable