Rollback on faulty update

In a resilient firmware update process, the ability to revert to the previous firmware image is crucial in the event of a faulty update. Does the nerves firmware upgrade procedure include a mechanism for such rollbacks?

A successful update can be characterized in multiple ways, and one straightforward method is for the firmware to indicate its status by performing checks and signaling its successful execution after bootup.

it’s resilient and even supports extra capabilities for reverting eg if firmware is valid, but screws up wifi or similar… from a quick search:

Nerves firmware updates protect against update corruption and power loss midway into the update procedure. However, what happens if the firmware update contains bad code that hangs the device or breaks something important like networking? Some Nerves systems support tentative runs of new firmware and if something goes wrong, they’ll revert back.
GitHub - nerves-project/nerves_runtime: Small, general initialization and utilities for Nerves devices

EDIT: looks like it’s NOT automatic on all systems see this section: GitHub - nerves-project/nerves_runtime: Small, general initialization and utilities for Nerves devices