17:42 <MWelchUK> sjg1, Tartarus: Looking at the git log, I think you may be the guys to talk to about bootstd....

17:42 <MWelchUK> Clearly this doesn't work on boards that are using bootstd.

17:42 <MWelchUK> have the bootcount support enabled in U-Boot.

17:42 <MWelchUK> On boards with distroboot enabled, we have an altbootcmd which will switch to an alternative extlinux.conf by setting the `boot_syslinux_conf` env variable before running `distro_bootcmd`. We have a tweaked version of OSTree that creates the relevant config file.

17:42 <MWelchUK> So, I work on an off with a distribution called Apertis. We boot on a number of arm32 and arm64 platforms, some of which have switched to bootstd upstream (such as the RPi4). For some of the use cases that we care about we want atomic updates and a rollback mechanism should an update fail. At the moment we are using OSTree for atomic updates and

17:42 <MWelchUK> I'm interested in your thoughts on what would be the best approach to implementing this in a bootstd world.

17:45 <MWelchUK> One option that I'd started considering was adding a `fallback` option in the extlinux file, that would point to a label as `default` does and add an argument to bootflow to cause it to select the fallback rather than default label.

17:46 <MWelchUK> We're looking for a solution that would be acceptable for upstreaming :-)

18:30 <sjg1> MWelchUK: Well, at present bootstd always uses EXTLINUX_FNAME which is "extlinux/extlinux.conf"

18:32 <sjg1> We could perhaps introduce parameters to bootmeths. so you could do something like 'bootmeth set extlinux filename extlinux/fallback.conf"

18:33 <sjg1> Then a bootflow scan would use that filename instead of the default

18:34 <sjg1> But perhaps it would be better to provide tighter integration between bootstd and bootcount, e.g. bootmeth_extlinux could automaticallly switch the filename to something else when bootcount is exceeded?

18:35 <sjg1> Re adding a 'fallback' option - is that part of the standard file format, or would it be a variation?