v0.2.36

v0.2.36 — fix U-Boot persisting fdt_addr

Switching DSI panels (a documented user action) moved the firmware's DTB and
the frozen fdt_addr in the saved U-Boot env then pointed at nothing, failing
booti on every boot in both slots with no recovery but a reflash. Shipped in
v0.2.35 factory images; no devices were in the field.

Also stops boot.cmd overwriting the release variant's bootdelay=-2, which had
been undoing the non-interruptible-autoboot hardening on first boot.