I always try to jump into these threads when I hear Onyx Boox mentioned. They're a lousy company that does not respect the GPL and ships intentionally insecure software (ancient linux kernel with SELinux disabled for starters) that phones home to Chinese servers. The bootloader is locked, so putting pmOS is out of the question and their update files are intentionally obfuscated.

I explain it all in this comment: https://news.ycombinator.com/item?id=21041543

This received some attention in the re--it community last month--the company still does not care [0]. It's a tragedy because their hardware is good, otherwise and they can compete on that.

[0]: https://old.reddit.com/r/linux/comments/hl09g7/onyx_boox_chi...

I own an Onyx Boox Max Pro 13 inches. I was happy with it, until the battery died completely after 14 months and the device started freezing continuously.