OK, the way this works (captured in the thread noted below) is great ... when the settings can be "shared" (used) by both of the partitions.
However, like some of the recent DSA changes => the settings may be incompatible between v19.xx (for example), and the master (so coming v20.xx?). This means you can't upgrade the master partition firmware, without resetting all your settings, every time - which is a bit painful, as it can often mean that the router is not initially functional
Just a thought, but ... would it make sense to allow saving / maintaining settings, but in the dual partition case having the option of which partition is used as the source for that save?
I might be misunderstanding, but if you have, for example, 19.07.3 on partition 1 and it's working well for you, but you tried a master build on partition 2 and it's not working well, you can always use use luci-app-advanced-reboot to boot back to partition 1 and upgrade from there again, that way partition 1 will always have your stable 19.07.3 build (or whatever build you want to keep settings for).
Yes, I can get back to partition 1 (v19.07.3) - not with luci-app-advanced-reboot, but with 3x power cycling, then it goes back to partition 1. But let me try to explain the issue. And assuming partition 1 is v19.07.3 as you note, and partition 2 is master.
If I am on partition 1, and want to upgrade partition 2 (which is how it has to be done, with dual partitions, the backup partition is always the one that is flashed). So I run sysupgrade (from partition 1), but ...
I can't keep settings => they are not compatible, and get pulled from partition 1, written to partition 2 on boot ... boot fails.
I can reset settings (not save them), but then ever time I reflash to partition 2 (master), I have to restart from scratch.
Make sense? What I'd like to do is ... have the option, when flashing partition 2 (for example), from partition 1 => let me tell it to restore settings, but using the ones that work with partition 2.
Clear as mud?
PS: BTW, the reverse is true also ... v19.07.x can't be upgraded either, and keeping settings. It's all because the settings are not compatible between the two.
Ahh ok, you'd like to save the individual settings you know work rather than just clicking save settings and saving everything. I think the way to do that would be to go into Luci>System>Backup/Flash Firmware>Configuration and choose what you'd like to save, I've never had a need to do it myself though so I'm not exactly sure what can be saved there and what can't, maybe someone who's used it before will see this this and be able to go into more detail.
Not quite . Sorry, I may have confused you. The issue is that when I'm on partition 1, wanting to flash and get to partition 2 => there is no way to not start fully from scratch every time. Yes, I can save the settings and restore them, but that means re-cabling, as the default settings won't work on my network (i.e. router is not accessible)
LOL! No worries, it's a bit odd, given the dual partitions. sysupgrade doesn't actually keep the settings from the targeted (backup) partition, rather it "mirrors" them from the active partition, to the one being programming. That's the issue ... can't really keep the settings in the targeted partition