According to that site you can downgrade the firmware (some people really disliked the various UI changes and the firmware is getting quite prescriptive)

You can also run your own homebrew apps so I found someone who installed KOReader which they claim is better experience than default reader especially for pdfs and also link better to personal cloud storage.

There’s also ability to use locally stored Web Application Frameworks but I’m not 100% sure what the use case would be.

If he retains an ownership stake doesn’t that mean he still takes home the profit of Brewdog so boycotting would still be effective/desirable?