From https://gitlab.tails.boum.org/tails/tails/-/merge_requests/1765#note_246796: When we upgrade the persistent storage (`UpgradeLUKS` in `tpsd`) we apparently try to mount the filesystem (via `test_passphrase()`), but this fails in this scenario since we have deliberately broken the filesystem so it is unmountable. So it is expected that this scenario fails, but why doesn't it do that on stable? Well, there is a bug in the Greeter on stable that I fixed in the non-atmonic WIP commit b9c4aa26a95b267cdd5624e577faad7f2cbd3121, namely the `return` I added in the `if self.tps_upgrade_failed:` case; we just set the label to "Failed to upgrade..." but without that `return` we'll proceed to set it to "Your Persistent Storage is unlocked ..." as if everything was successful.