Well, I am using armbian, but the R1 is depricated there as well.
Currently we are trying to get mainline Kernel working with a differnent driver for the Switch, but Multimedia wise it might lack of some functions.
Depricated, we are a few testers but no one who can develop. If someone steps up and does together with the testers some fixes before new releases (twice a year) - Igor will take it back to supported.
Did you have some sucess with the shorter cable already?