[timonoko]

You can strap Raspberry to your phone via USB and you have 100% Linux phone without restrictions. Communication happens via Phone's USB-tethering and Raspberry's Internet-via-USB (and bVNC). OTG-phone can also power the Raspberry.

I used this setup a lot, but nowadays Termux with X11-server is good enough.

Most use nowadays is photo editing with GIMP. You can gain excellent dexterity with bVNC with time.

[nibbleshifter]

I'd been considering working out a way to do this over Bluetooth networking for a while - have a Pi0W on a power bank in my bag, hooked up to phone over BT for when I want to test something quick on the go (ideas often happen on buses, subways, etc).

Might tinker with it this evening.

[axytol]

Thinking of the Pi0, I assume you would need 2 usb cables and a hub: 1 cable goes to Pi's power usb port, 1 goes to the other usb port for connectivity, then both cables joined through a hub to the phone's usb port.

[timonoko]

May have been also that when you connected Pi to a power source it powered the phone too. I was using this system 10 years go with very cheap phone without OTG, so Pi was solution to this and other problems.