So what Linux distributions are supported by the multiboot image exactly? Here’s the list:

Arch Linux Arm 2020-09-08
Lune OS 0.113
Maemo Leste 20200906
Mobian 20200912
KDE Neon 20200912-132511
pmOS / fbkeyboard 2020-09-11
pmOS / GNOME 2020-09-11
pmOS / Phosh 2020-09-11
pmOS / Plasma Mobile 2020-09-11
PureOS 20200908
Sailfish 1.1-3.3.0.16-devel-20200909
pmOS / sxmo 0.1.8-20200726
Ubuntu Touch 2020-09-10