[] Signature spoofing doesn't work on a freshly flashed xperia 10 plus

Good luck, as until now I did not see that this is noted by Jolla as a problem at all.
Maybe it is an upgrade problem, maybe wrong execution of steps? But until now we also did not see any positive feedback where a user has spoofing enabled under a freshly flashed system, right?

No, not really. Only way to acknowledge is the like (heart) button. (which has only been pushed once as of writing this here)

I also have this problem on a freshly flashed 3.4 device. An XA2 Ultra single sim specifically. Seems like it’s not an adaptation-specific issue?

Random thought: would someone be willing to try the old method of enabling spoofing to see if that still works? I have a bunch of travel this week so I can’t.