Maximum time in dfu

[alfalejandro]

Is your feature request related to a problem? Please describe.
After an OTA update failure, the NRF is stuck in DFU mode and cannot connect remotely. It is installed in a hard-to-reach location.

Describe the solution you'd like
I think there should be a maximum time limit for DFU mode. For example, 6 hours; after 6 hours of DFU activation, it should automatically reboot and start up with its current firmware.

Describe alternatives you've considered
I can put a watchdog timer that restarts the power supply if there's no activity on a pin, but that adds unnecessary power and hardware when it should be possible to do it via software.

Additional context
Thank you for what you do

[fkallay1]

#48 (against dev) covers the situation you describe, though not as a limit measured in hours.

What it does. Once a transfer has actually started, the bootloader supervises it and reboots 15 s
after the last activity. An update that dies mid-flight - client killed, cable pulled, link lost - no
longer leaves the device waiting indefinitely; it recovers by itself in seconds instead of needing
someone on site.

What it does not do, and this part matters for your case. It supervises a transfer that has begun,
so it is not a general time limit on sitting idle in DFU. And there is a harder limit than any
timeout: once a failed update has erased the application - which happens as soon as bank 0 is erased -
there is no "current firmware" left to boot into. No time limit can bring that back; the device has to
stay in DFU and be re-flashed. If your failures happen before bank 0 is erased, for example a
rejected init packet, then the application is still intact and #48's reboot does put it back.

What can be improved for a node you cannot reach is that it comes back reachable. #47 makes an
interrupted serial/USB update come back on USB instead of vanishing from it, and records the transport
so an interrupted BLE OTA resumes on BLE rather than being re-routed. #49 makes a retry actually write
the image - today a retry after an aborted transfer can report "Device programmed." while writing
nothing at all, which was measured on two boards. Together those turn "stuck, needs a site visit"
into "retry from where you are".

[oltaco]

Is your feature request related to a problem? Please describe. After an OTA update failure, the NRF is stuck in DFU mode and cannot connect remotely. It is installed in a hard-to-reach location.

As stated by @fkallay1 unfortunately after you have started an OTA update there is probably no longer any valid application firmware that can be started, so the only way forward is to update successfully, either by OTA or by USB.