Recovery

Recovery

Four ways back onto a working system, in order of severity. Read against NebulaOS-firmware at b95b156; the shipping release is 1.0.2, firmware 3bdf3ff.

Only the last of these loses data, which is why they are presented in this order - both here and in the end-user manual.

1. The automatic trial - nothing to do; see Image install and the trial.
2. Swap the boot slot from the screen - machine.nebulaos.system.swap_slot, which calls nebulaos-slot-swap. Blocked while printing.
3. SSH - both NebulaOS and stock accept root. Steps are in docs/HOW_TO_SWITCH_STOCK_AND_CUSTOM.md.
4. USB recovery - the SoC's mask ROM, which works when no system starts at all. Two very different operations live here: tools/recovery/usb-set-boot-slot.sh rewrites only the marker and erases nothing, while writing a full .ingenic image rewrites the printer and erases the data partition. See docs/DEVELOPER_RECOVERY.md.

Before reaching for any of them: why did it stop?

A printer that restarted by itself has already written down what happened. The black box explains /run/nebulaos/last-reset, logs/reset-history.log and the crash copies under logs/crash/. Reading the verdict first is cheaper than any recovery route, and it is the difference between a freeze, a crash and somebody's power strip.

The full procedures

This page is the map. The step-by-step procedures stay in this repository's tracked docs, which are the maintained copies:

Route	Document
Swapping slots, from the screen or over SSH	docs/HOW_TO_SWITCH_STOCK_AND_CUSTOM.md
USB recovery, both operations	docs/DEVELOPER_RECOVERY.md
What the slots and the marker are	Architecture

Two corrections those documents now carry, because their older prose predates the code: there is still no automatic rollback to stock, but a stock boot no longer leaves the MCU carrying Creality firmware until someone intervenes - S50nebulaos-mcu-guard and mcu_restore.py reinstall the native build on the way back, bounded and verified. See Architecture.

Not covered here

Nothing on this page was performed on a printer by its author. The USB recovery route in particular is described from tools/recovery/ and docs/DEVELOPER_RECOVERY.md, not from a run.