Biscuit
github.com
github.com
On the device itself, for the price it feels like a very well built device and the screen is not bad at all. Took a few weeks to arrive in the UK from China. Can highly recommend if you want something small/compact for reading on the go that isn't your phone.
I've been looking at getting an e-reader in the last few days, and the Xteink X4 is one of the ones I considered. I think it's probably too small for my intended use, but it's cool that people are tinkering with it like this.
But for those that want that, I guess this is a cheap version?
I personally hope this could drive more sales for those who don't necessarily want an ereader (or already have one) but are interested in tinkering with it (I doubt anyone looking for gaming or messaging will pick it, seeing it's still more expensive than a proper Android phone), and thus lower the price of future models for everyone.
There's probably some niche where ridiculously long battery life (plugging a small solar panel will effectively make it self-sufficient) and sunlight readable screen with very basic apps would be welcome.
other devices may / may-not have RTC clocks or "easy" access to longer-term RTC-style running.