If I remember right, (it’s been a while since I did it), I think you don’t need the chroot part on X. Just mount Sailfish_home to /mnt, and cd to mnt and roots should be there…
Another thing that might help with a brick is fastboot flash system file from your original download zip. If the system was unmodified, it should flash back without any effect on your data…
In the end that was what did the trick. I was under the impression repeating the whole upgrade process is necessary. At first I tried to enable ethernet forwarding in order to use my desktops internet connection while in recovery. That was fruitless.
Somewhere in the process I also enabled the ‘rescue usb connection mode’ allowing me to ssh into the running system. I knew from the journald logs that Lipstick couldn’t start. All the rest seemed intact. No factory reset necessary. So I tried manually enabling wlan0 interface in order to redo the upgrade (no dice thanks to rfkill).
Literally the last thing I did before calling it a night was executing ‘pkcon update’. 2 Minutes later Lipstick came to life asking for my lock code. I had left the zypper cache alone even though one ZenDesk article I consulted suggested removing it in case of a failed upgrade .
Lucky me…
I understand why in some cases removing the zypper cache is something you would want to do on failed upgrade and why they recomend it, but on 3.3 -> 3.4 upgrade my Xperia 10 got stuck to the point the recovery console without internet and broken pkcon was only I had and using zypper to complete the upgrade from already downloaded cache saved me from doing factory reset or reflash.