[metadat]

Did you try direct wiring to bypass the battery?

E.g. https://www.instructables.com/Power-an-Android-Phone-Without...

[livueta]

Nope, and that definitely would have helped, but I bet 99% of people looking to use an old phone as a server aren't going to do all that either.

[asimops]

With most new phones not being designed to have swappable batteries like the S4 anymore, could this be modified by replacing the cells with a capacitor and then powering the phone from USB?

[tonyarkles]

Would be worth an experiment potentially but it’ll depend on where the protection circuitry lives. A modern BMS chip is relatively complicated and will freak out if the attached “battery” is doing this that wouldn’t be safe for a LiPo cell (eg a capacitor will happily drain to 0V but a LiPo drained to 0V has probably been destroyed)