Loading display drivers in initrd (~3s) before RP1 PCIe southbridge
is ready (~12s) causes 'Cannot find any crtc or sizes' because the
DSI encoder isn't reachable. Rex loads these via udev late in boot.
- boot.initrd.kernelModules: only ocp8178_bl (backlight, RP1-independent)
- boot.kernelModules: vc4 + panel_cwu50 loaded in stage 2 after RP1
Rex's Trixie images use [pi5] for the CM5 display overlays
(clockworkpi-uconsole-cm5, vc4-kms-v3d-pi5). The nixos-uconsole
module generates [cm5] which the firmware may not apply on
some CM5 EEPROM configurations. Adding explicit [pi5] section
ensures the display overlays are always loaded.
The ter-v24n Terminus font renders garbled on CM5 DSI 720x1280
panel (green stretched line across screen). Switching to the
kernel's built-in Lat2-Terminus16 font for correct text rendering.
GPIO 23 service used gpioset 0 23=1 on BCM2712 chip 0 instead
of the RP1 chip (base 512), writing to a critical pin and
freezing the system. Commented out until correct chip is confirmed.
SSH opened with PasswordAuthentication + PermitRootLogin for
first deployment. Lock down after initial boot.
sysfs node is read-only (0444), even root cannot write.
The AXP228 PMU manages power path in hardware.
Practical fix: disconnect batteries during heavy builds.
The nixpkgs attribute for userspace GPIO tools is 'libgpiod',
not 'gpiod'. This provides the gpioset binary used by the
GPIO 23 internal USB hub service.
Disko auto-generates fileSystems with by-partlabel paths, but
for manual install via loop devices we need by-label paths.
mkForce ensures our paths win during evaluation.
disko module defines options under `disko.devices.disk.*`, not
`disk.*`. This was causing evaluation error:
"The option 'disk' does not exist. Did you mean 'disko'?"
- Add disko flake input + partition config (/boot/firmware, /, /home)
- Add cm5-backlight-fix service as display fallback
- Add enable-gpio23-usb-hub service for internal USB hub
- Add mt7921u kernel module for MediaTek AC1200 WiFi
- Add gpiod package for GPIO userspace control
