The doc still described the May 2025 design (hard-coded /img/ paths,
`quiet init=/bin/sh` cmdline, "2-5 second boot"). Update every section
that was inaccurate after the boot_images / autologin / earlycon
fixes:
* §1 Overview — boot time 30-60 s (full systemd graph), autologin
to root, link to BOOT_IMAGES.md.
* §5 Boot sequence — added the provider.get() step and the
systemd serial-getty autologin step.
* §12 Boot Images — full rewrite. Documents the three asset slots,
what configure-pi3-autologin.sh patches in (drop-in + shadow +
service masks), the three storage locations (binaries/, named
volume cache, manifest.json), and the "refresh to a newer Pi OS"
runbook end-to-end.
* §13 QEMU launch command — new cmdline with
`earlycon=pl011,mmio32,0x3f201000` (without it the kernel can't
set up the PL011 UART early enough and boot is silent) and the
kernel-must-be-decompressed warning.
* §14 Known limitations — realistic boot-time entry, plus a new
"boot file size" row noting the ~7 GiB volume requirement.
* §16 Key files — added boot_images/ module, manifest.json,
configure-pi3-autologin.sh, upload-binary.sh, binaries/ host
dir, and the docker-compose boot-images volume.
93ad8fac6a
