Runbook — clean-slate build with an eMMC reader#

The path a recovery or a fresh build actually takes: OS first, application on top, MCUs usually last — and often untouched, because layer 2 survived whatever killed layer 3. This is the order verified end-to-end on the reference machine.

1. Inventory your backups#

Minimum viable: the config set (git repo or any copy) and the MCU state. Already-mainline MCUs need nothing here; vendor MCUs need the firmware steps below. A full eMMC image makes this a restore instead of a rebuild. → Recovery

2. Flash the OS#

Pull the module, flash it offline, preseed the rootfs, boot configured. Verify before proceeding: boots, joins WiFi, eMMC at DDR52 37.5 MHz effective. → Clean-slate install

3. Install the application stack#

KIAUH — Klipper (master), Moonraker, Mainsail + config, Crowsnest — plus the extras you use. Enable CAN on the host and install scipy in the Klipper venv. → KIAUH stack and plugins

4. Restore the config#

printer.cfg with its SAVE_CONFIG block, saved_variables.cfg, moonraker.conf. Fix absolute paths if the OS user changed. A missing section means its plugin isn’t installed yet — install it, don’t delete the section. → Klipper config: restoring from backup

5. MCUs — only if they’re on vendor firmware#

If they ran mainline before, they still do — klippy connecting to both CAN UUIDs is the proof. If they’re on vendor firmware, do the firmware steps: build then flash both MCUs.

6. Verify bottom-up, then print#

eMMC clock (layer 3), both MCUs respond (layer 2), klippy ready (layer 4), then a supervised first print — watch the first layer. The tap reference recovers from a config restore, but only a real print proves it. → Calibration