edk2-msm

You may want to look into things like: https://projectsandcastle.org/status. Like the other commenter said, iOS is locked down and I don't think Sandcastle supports iPad (it looks dead now). If you want a Linux tablet, look at the JingPad, or just any old Android tablet. There is a chance you could go through _lots_ of work to get some _Android_ device to work on raw Linux with the edk2-sdm845 UEFI firmware (https://github.com/edk2-porting/edk2-sdm845) that chainloads from the Android bootloader (ABL).

right! thanks! i forgot about the oneplus6 & it's progress! figuring out how to get a kernel & normal environment booting seems to be one of the biggest challenges. there is a TianoCore EDK2 porting effort underway that seems to have support on a good number of phones. who knows what works & doesn't once you are able to start running your own mainline kernel, but way cool to see over a dozen phones on this list! genuinely excited to have some 3(+) year old phones (mostly now unsupported, insecure, or about to be!) to start to get to play with!! this could well be a flagship demonstration of what a Right to Repair can do: save a lot of devices the landfill, prove very enduringly useful to people, once they have some self-determinism with their purchases. ad astra emptor. https://github.com/edk2-porting/edk2-sdm845