This patch file mirrors a commit that already existed in checkouts/talos
(`a50511de7` — "grub: EFI-at-/boot fallback for BOOT-less SBC layout in
Upgrade path") but was never landed back into patches/siderolabs/talos/.
Extracted with `git format-patch` from the checkout so subsequent
`make patches` runs reproduce the same tree on a fresh clone.
Complements 0005 by handling the Upgrade code-path (in addition to the
fresh-install code-path 0005 already covers) for SBC layouts that don't
have a separate BOOT partition.
