Now I did update on one of my Xperia 10’s and @Stevo , you are right, there is no button.
I ran into the same problem because I forgot to deinstall Chum before updating.
So the following happened:
I looked for new updates manually (as always), device told me that update is available.
Started download, while downloading it reported that I shall delete the Chum-gui app, but I couldn’t do anything at this point.
So I let the download proceed until the end, then I did NOT pulldown+install BUT swipe up and app grid appeared.
At this time I was able to deinstall Chum-GUI by long tapping the icon and then tapping the x. Additionally I deinstalled Storeman.
After this, I closed the app grid and proceeded with the update with pull down → install.
It went fine without issues.
edit: GPS receives 28 satellites after a few seconds (much faster than before), but still no position fix after several minutes. (0/28) edit: Under conditions where Volla Phone and a Garmin GPS finds the position within <10 sec., X10 no fix. Under better conditions pos.fix is possible but altitude is wrong. Real altitude is 645 m ASL, displayed by Garmin & Volla (and a map). Sony X10 displays 670m. Before the update X10 displayed 680m.
reinstalled Chum from https://chumrpm.netlify.app/ - works.
Storeman reinstallation was fine using Storeman installer from Chum but now it updates database forever. edit: now it asked twice for permission and has now ready updated and everything’s fine.
Browser much better now!! Thank you Jolla!
edit: Update on my other Xperia 10 also successful. Thanks again Jolla!