I just have here a simple router/repeater made of an old but fully functional Raspberry Pi B (1) and a WiFi adapter running 18.06.x.
Now with 19.07.0, I tried to sysupgrade first using LuCi, and after a fail, with a ssh terminal, copying the sysupgrade file to the root fs and trying to run sysupgrade manually.
Both didn't work.
I've made a couple of tests and tentatives, but in summary, what seems to me is that this is a work that is not completed so far (the main finding is that the sysimage is ~280Mb long and the /tmp ramdisk partition, mounted, has above ~230 Mb; it can't work this way).
Of course the next step should be doing a backup config / fresh install / restore config. Anyway, I would like to check with friends whether there is anything I can do for getting sysupgrade working in that platform, which seems to be more difficult but may help somebody else. I know Linux, shell script and C a little bit and possibly I can help in this case.
I think the first question - for the gurus - is how huge is the gap to be filled in this case.
lramos dot prof at yahoo dot com dot br