If you want a functionnal Linux on your device, it's not going to be cheap and easy.


Solution 1:
would be to adapt libhybris to get it working with the distro so the phone could use the Android drivers.

Ubuntu Touch was the only desktop-style distro doing it on a large official scale. But they've quit.

Gentoo and Arch being hacker friendly should be the easiest, but one would need to pay devs to do it.

Other distro might have devs and might get paid to do it (I know that opensuse has shown interest in ARM netbooks/chromebooks in the past).

The good thing : you can release such a device now with only Android and SFOS support, and add the Linux distro later when it's working.



Solution 2:
- redesign the device to use only parts with at least official linux support.
(That's how most netbooks/chromebooks did it.
Pyra is partially going this way, regarding the GPU)
That's going to require some redesign (probably custom PCB) and select parts which aren't optimal (different power drain needs between chromebooks and smartphone)

And by the time the things is finally done, released and start shipping, users will complain that its specs look outdated compared to the latest iPhone Galaxy 9 Plus whatever.

The only reason that Pyra is managing to ship at a not to glacial rate is that they could leverage a lot of past work (e.g.: the main board is actually an evolution that Golden Delicious did for the Openmoko upgrade "GTA04") combined with Texas Instrument OMAP SoC having pin-compatible variant (they could basically replace the SoC with the latest available while keeping more or less the board).



Solution3:
- have paid developers do the reverse engineering for the GPU
- use as much standard component for the rest
so any modern kernel could work on it.
- design a completely custom solution around the above.

This is tremendously complex work for a phone.

(The only one I know who managed to pull it was the OpenMoko.
And it still took ages before coming out and looked outdated.
And they used very carefully crafted platform (both GPS and Cell-modem are completely self-contained chips that simply talk to the main system over a serial COM port.
The GPU has a weird architecture that can completely be short-cut around a 2D rendering done while the 3D was only closed soruce.
The Wifi and bluetooth are on purpose standard cores that have similar desktop drivers.
etc.)