

Not all ARM chips are in phones, nor are they all locked down like one. There are several ARM devices and SBCs now where switching OSes is as easy as swapping out an SD card. Most do use uboot as a standard and some are even capable of utilizing UEFI.
Terminus is nice and has a lot of platform options. Ive used on an old ipad in the past. If you have several machines, I highly recommend servercat. Works wonderfully on iphone, ipad, and Mac. It also has options to write and store commands to easily send out to any number of devices with a taps/clicks.