Well, my PSP had its battery inflate. I had replaced that battery a few years ago, used it a bit, then forgot about it. Recently found that the new battery is in oopsie state too.

It's not just degradation.

And PSP is still a fine device. Actually amazingly useful, it's the missing branch of evolution that should have been chosen instead of smartphones. No touchscreen, but convenient controls. If it only had a SIM port. There even was a Skype client.

A general purpose device and not a gaming one, like PSP, would be very good. Instead of that proprietary optical drive - additional ports and memory card slots, perhaps even a section with an interface for some extension chips. A similar set of buttons - except perhaps a retractable (or attachable via some interface) QWERTY keyboard would be useful.

The UI and UX of the OS were very cool. OK, I was using it for listening to music and reading books.