I started over with a freshly installed Debian 9, and then with again with a completely empty .armory folder too. v0.96.4, local ArmoryQT connecting to remote ArmoryDB.
Again, the same symptoms, it stops scanning at "one minute left" with those hexit errors.
I did everything exactly like always, with dependencies and commands from old written down notes.
So it can only be something broken at my ArmoryDB, or a general imcompatibility with the Qubes OS Debian VM templates, or a networking problem in between?
Ente