The update didn't go well for me. At the end of the process, I got a screen telling me that there was an error and the phone was not updated, and asking me to reboot. Now the Jolla C won't boot, it's stuck on the white Jolla and Sailfish logos on black screen and will stay there for hours.

Please note that the issue is probably related to my device and not to the update, I had been fiddling with the logical volumes sizes in recovery mode due to some problems before trying the update (but I thought I finally completely solved them when I decided to go forward with the update, everything seemed to be OK again). I don't mean to discourage people from updating as I have no clue whether this is just bad luck or a pre-existing problem on my end that did not go well with the update (and I suspect this).

I'll probably have to do a factory reset, unless someone has another idea?

Requiem_76, would you mind describing the steps you went through in recovery mode to solve your boot issue?