Any one that works? lol. Actually it was suggested to me on the Hardkernel forums that RT patches won't work until kernel 5.1 maybe which I see you have gotten 5.1 to run. Unfortunately no RT patch set exists for 5.1 yet.
Anyone working on an RT-preempt patched kernel for the N2? Probably not the place to ask but I'll pull my hair out trying to get a patched kernel going (I've tried).