Good day,
Well, I know the ARM port is unsupported and all that, Haiku is not for touch devices nor for phones, the Haiku ARM is still in diapers, and does not target the Pinephone nor Pine64 SOC boards. Nonetheless, as I have a Pinephone I tried, just for the fun of it, to get Haiku to boot. I wasn’t expecting a Desktop or anything other than the Haiku boot screen and a jump to KDL afterwards.
Actually, the Pinephone didn’t use the SD card to boot. It didn’t find it bootable, maybe because I burned the Haiku ARM image with Gnome Disks, and the file format is .image. Don’t know.
Actually, this is the only ARM device I own, so it’s the only one I can do testing onto. Though I still don’t have the tools and knowledge to go farther in the research. Hopefully will sooner than later. Maybe a Pine64 SOC board could be a nice idea to do the testing onto, before attempting at booting the Pinephone… 
Well maybe someday it will boot. 
Regards,
RR