Thanks for the information. It helped me replacing my Nova2's battery. Mine died in about 3 years

. Are all of BOOX devices like this?
I bought a replacement battery from
here, but I don't recommend them. They claim shipping out within 1 day, 3800 mAh capacity and some replacement tools, but the shipment started after a month

and arrived with only a useless phillips-type screwdriver and
3500 mAh capacity

. But at least size matches to the original battery. Pic1 is a comparison before I detached the original battery:
About my experience: not having something better, I opened the case using a kitchen knife. Not so gentle but with a bit of patience it worked (though it left some dents on the edge...). My main struggle was removing the old battery. Two strips of double sided tape underneath were quite strong and I was afraid of damaging something (e.g. flat cables), but it was doable, with a credit card and patience (Pic2). First I briefly tested the device by connecting the new battery via the connector. It worked (meaning device turned on) but eventually I soldered wires to keep it as done by the manufacturer. So far my Nova2 seems fine (back to normal battery life, no freeze, no sudden battery drop, no shut down). However, it didn't charge to 100%. It stopped charging at 90%. I suspect this is because of battery calibration; Nova2's original battery is 3150 mAh and 3150/3500 = 0.9...