Both installers now fail fast if booted non-UEFI or warn on Secure Boot,
since GRUB install/NVRAM registration silently "succeeds" in both broken
cases and the failure only surfaces on next boot. mkfs.btrfs now forces
past leftover filesystem signatures on reinstalls. build.sh patches
nomodeset into every boot entry (BIOS/UEFI/PXE) to work around early-KMS
hangs on Optimus laptops (e.g. Lenovo Legion).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Amir Alexander Abdelbaki
9cd8eb2065