LCNC on BeagleBoard AI64

I’m trying to run linuxcnc on BB-AI64 (looking for a "natural" upgrade path for the machinekit on BBB that we’re using since 2015).Some months ago I manage to install the official image debian 11.3 2022-06-14, then upgrate to kernel 5.10.109-ti-arm64-r49 and install linuxcnc from debian packages (it’s a 2.9.0-pre0+git20221105).
Of course the system was not rt and then as expected the latency test exhibited very poor results both on base and servo thread (we don’t need soft stepgen: in BBB the axis are controlled by CAN with a driver running in the PRU, and we planned to do the same in BB-AI64, anyway the latency on servo was too high without rt). Linuxcnc seems running ok: latency test runs and also the sim mode of linuxcnc.Recently I’ve update to kernel 5.10.168-ti-arm64-r103 (still not rt, same results) then to 6.3.1-rt-arm64-k3-r16.
This latest is a preempt_rt kernel (the first and only one I was able to succesfully install on AI64) but results are not as expected: linuxcnc latency test starts but the results windows is not updating (all values are 0). Also when I start linuxcnc sim (the basic demo, axis.ini, that was normally runnig on “old” 5.10 non rt kernel) it ends with error window in the loading/init process.

I've then try running from the scratch: I followed the instructions on linuxcnc.org/docs/stable/html/code/building-linuxcnc.html and been able to compile it without errors, but the results are the same as with pre-built package installation. Tryed both 2.9 and "master" (2.10) versions without any markable difference in results. 2.8 have no valid configuration for bullseye-uspace so dependencies are not well defined and compilation result undeterminated (I've trusted the warning and not tryed to compile).

So actually the state is a working (but useless due to latency) LCNC on kernel 5.10 not RT, or a not-working (so still useless) LCNC on kernel 6.3 RT.
I've no idea on how to go further

I forgot to attach the info/debug files that LCNC outputs when I run it. Not very usefull anyway (at least to me).

You may get good results checking out the pocketNC (now Penta) repo. they have been woring with the BBAi for a while now.