> I've done some more testing. What is failing is installboot while > trying to set an EFI variable. Managed to run installboot with the -v > option during this step of the upgrade as shown in this picture to get > additional information. I'm not using FDE and sd0 is the right disk to > use.
I think I've found a workaround. At some point installboot looks for an unused Boot000* variable. In my case all of those were already used, and several duplicated. So I had to boot Arch Linux and use efibootmgr to delete Boot0004 which in my case was duplicated and not used, something about NIC boot. After that I tried sysupgrade and everything worked fine. Hope it helps.
