# PC boot media (generic x86-64, UEFI)

`make boot_image TARGET=PC` builds `build/boards/pc/lithos-pc.img`: a GPT disk with one FAT32
EFI System Partition, for any x86-64 PC whose UEFI firmware boots a removable medium. Write it to
a USB stick with `dd`. The partition holds:

- `EFI/BOOT/BOOTX64.EFI`: the amd64 monolithic loader, with the whole kernel embedded. Firmware
  finds it through the UEFI removable-media path, so no boot entry has to be created.
- `startup.nsh`: runs the loader if the firmware drops into the UEFI shell.
- `starforth.cfg`: the boot arguments -- `system=v4` as built; change the word to `system=v3` to
  boot v3 (and `KERNEL_ARGS="..."` adds to it).

Beside the image, `lithos-pc.spdx` / `.spdx.json`: its SBOM, every file on it with its SHA-256.

Nothing in the image is specific to one machine: it follows the generic UEFI/ACPI path in
FABRIC-3.md §III. Until 2026-10-14 this target was named `SER5`, after the first PC to be brought
up -- a Beelink SER5 (AMD Ryzen), which is still the one on the bench (`boards/BRINGUP.md`).

Status: booted in QEMU (q35 + OVMF, from this image as its own disk): v4 as built, v3 with
`system=v3`. Not yet booted on real hardware.