@qwerto, KOReader actually works for keyboard readers. I tested it on K3 and DXG. I haven't heard anyone tested it on Pocketbook 912 though. You can give it a try. We probably need to adjust the keyboard mapping a bit for 912 since it might have different keycode for each key. Other than that, everything should work out of box
You found any issue, feel free to create a ticket on github so other developers can follow up on it.