I managed to update my Reliq to 1.20! Not quite sure what I did differently, but maybe the updater just doesn't work on Sundays ;-)
In case this helps anyone else:
- I used the supplied cable with a USB A --> USB C adapter on my MacBook's side, and the MacBook running off its internal battery.
- I started up the updater app first, and only then the Reliq. I didn't touch any buttons or encoders.
Yesterday I first got a few errors somewhere along the transfer process. After a few tries, the file transfer seemed to succeed, but the Reliq stayed frozen on the 'waiting for the update file to arrive' message. Today it just worked. Strange but true.