Mobian works on FP4 (just looks like it does not)

After installing, on booting, the phone vibrates once, and then comes to a black screen (the screen is active, but black). Mobian is active now, but it is not displaying anything.

To get to the Mobian login page, you must repeatedly press and release the power key - I think five times in all. Each time the screen will power up, then power down, remaining black, but in the end, the Mobian login screen will appear, and you can log in.

I will close here who wants to follow-up please do here