Just for information, my device was also bricked after upgrade from Saimaa to Taalojärvi failed then recovery mode/factory reset failed too after having returned "Recovery procedure terminated SUCCESSFULLY! Now cleaning up..." (then nothing happened until I removed the battery, two hours later).

Recovery mode now unavailable. No device detected on USB.

Submitted a ticket at Zendesk, but they are in vacation from June 18 until August 1st. Ticket closed automatically. So we have one and a half month with zero customer support.

Anyway I should have done like for previous upgrades: factory reset FIRST (after back-up of course). Fortunately I do have a back-up of /home and /etc.