Can the OPI5 be Configured to Run LCNC?

Hello Royka, I noticed that in the image you shared, /lib/modules are missing (broken link...) 
I found under boot/lib/modules maybe what could be copied/moved?
Are you aware about this issue?
I'm not an expert.. but I'm getting errors and finally it's impossible to install or configure anything else: I tried to share a folder with Windows PC, I tried to install a VNC server, wifi adapter.. no one USBs are working (except for keyboard and mouse in USB3).
What I can understand all these issues are most probably related to missing modules, right?

[Update]: I investigated and the issue is caused by the fact that Boot partition is considered as removable storage.. don't know why.
I'm using  Win32DiskImager for the creation.. should I do something once SD is created? 
I tried to copy modules from boot to usr/lib and the situation now is beter, USB are working..
 

I'm aware of the error message at boot, but where is the broken link? What are you missing?
To share a folder with Windows, you'll need to have samba installed, although I recommend to install winscp on the windows machine.

The standard vnc server won't work on wayland.
Normally spoken gnome-remote-desktop is the only one that works that I'm aware of, but somehow it doesn't show up in the gnome-settings. I'll have a look at it when I've time for it.

Which USB devices are you trying?

There are not a lot wifi drivers installed indeed, you could check /boot/config-5.10.110-rt53 to see which drivers are in the kernel. Actually "rtl8821cu" seems to be the only one as module. If you think you miss one of the modules from that folder you could sudo insmod ...

It could be that I did not add the boot partition to /etc/fstab but I don't think this causes the issues you've got. In /etc/fstab you could add:
UUID=5b681169-45c5-4093-b294-370b651abe59  /boot ext4 defaults,noatime,commit=600,errors=remount-ro 0 1

Yes Royka, thanks, I know more or less these things, I will try to install TigerVnc, I think it's ok.. but without fixing modules was impossible.
The broken link is inside /usr/lib/ you can find "modules" that is broken link, pointing to "/boot/lib" but boot partition is localized inside "media" because recognized as external drive (strange).
About USB I was trying to use a standard USB key, not working, not recognized at all without fixing modules.
Finally I solved deleting the wrong link "modules" inside /usr/lib and I copied and pasted whole modules folder from media/.. /boot/lib/modules inside usr/lib and now the error at boot disappears and also I have the possibility to install something.

About HAL configuration.. are you using ARISC driver for GPIO? 
I have my configuration working with RPI4 but I imagine the same driver would not work.. right?
I will try next days.
 

As I said, adding that line in my previous message to /etc/fstab would mount the boot partition at /boot, to be sure you could type blkid to check the uuid, then the link would have been correct. What you've done also works at the moment, but when the initramfs needs to be updated, possibly it makes a new file in /boot which will not be in use.

Again TigerVNC won't work in Wayland.
You could try to follow the instructions from:
discussion.fedoraproject.org/t/how-to-st...ession-wayland/78971

I don't use the opi5 at all for LinuxCNC and I've got a mesa board over ethernet. I was just curious if it would work, I might use it later.
The arisc module could work, personally I wouldn't use the gpio pins without something like a CNC shield/hat to protect the pins and most sensors/steppers needs 5v, the gpio pins are 3.3v. But that's the same as with the RPI4 so perhaps you already own one?

After reading about the arisc module, this is using the internal mcu, so I think this has to be ported to make it work with the opi5.

You are right, with the additional line you posted the issue is fixed.
I will play around the GPIO driver because I want to replicate what I did for my RPI where I created a PCB  transforming signals, inut/output and also Modbus. So I should also to find a way to use the serial from OPI5. The way still long... 
When I have something that make sense (as HAL) I will share.
For VNC I'm not able to find a solution, I read a lot about gnome-remote-desktop but all places explains to configure thought setup, but it's not visible.. not urgent, now I try with Samba, it's more helpful to pass ISO G files with shared folder but I already did in the past.. then I have to configure 7" display, I found some hints on the web... 
 

Yes somehow the gnome-remote-desktop is broken on that ubuntu version.
I've just compiled the rt kernel, which I'd tried before, but this time with the config of the existing build and enabled the panfork drm and disabled another option which is necessary to use panfork. Till now it seems to do good, but I've not tested the latency yet, I'll do this weekend.

If the latency is still as good, it means we will have hardware acceleration and have the ability to enable wifi drivers, remote desktop etc.

A quick test, without full hw video decoding yet, but 1080p does work fine.
Or the results are really this good or if hung, although the timer still worked. Need to do some more testing.

I will be very interested if it is viable. I've been mucking around with the build you gave me, and realized not having wifi will be somewhat of a problem. I tried getting one of my Netgear rtl8192cu usb dongles to work, I tried adding a PPA that maintains most realtek drivers, however when I tried to add the driver via the synaptic package manager or command line, I get an error. At first I though it might be because the drivers are built using dkms mode and Arm64 just doesn't like that, however reading that this build just doesn't have wifi. I guess that would explain part of my problem. I'd like to be able to use a usb wifi dongle so I can free up the ethernet port my Mesa board and still have internet access. Maybe this new build could make that happen.
Cheers!

I think wifi is a seperate kernel module so if its been left out, then you should look for the realtek driver and build from source if necessary..
DKMS is definitely supported under armbian.

With my previous test I did a dirty install of the debian packages and had to force install some packages. Now I've removed these and compiled LinuxCNC and it really does work as well as it seemed to be. So it's actually pretty easy to build your own image/kernel with Armbian, you only need to change the kernel config and source, after that you could build it as usually.

If you don't know how to do this yourself I will make an image, but it shall help yourself to make your own so you'll always be able to update and customize it the way you want. I don't recommend to adjust any timer/scheduler related things, adding drivers should be ok, although a bad driver (in use) could increase latency.

The screenshot was while playing a 4k youtube video, 8x glxgears and "stress --cpu8". cpu stress did improve the latency, so made another without.

Till now the only thing it doesn't like is playing a youtube video in the background, but who wants this while machining. It eventually will freeze the video and this also raised the latency up to 30us. This freezing is something I saw with other images too, should be a driver issue. Besides that, you could do about anything without getting latency.