Well if it was for a tech job im sure you could’ve shown off some troubleshooting skills haha

And the ArchWiki link is perfect. Ill read up on that and ensure I’m using it correctly. Thank you very much for the pointer kind stranger! :)

I’ll ask! How do you know? Lol

All jokes aside, I think this might really help me with a side project I’ve been working on. Ive been trying to get full disk encryption working on a NanoPi R6S running NixOS. The issue that im having is that im not sure exactly what modules I need in the initrd. When I boot, there is no output on the display after systemd-boot shows.

The manufacturer puts out a version of Ubuntu thats works flawlessly so I know its possible. But I’ll pass on the snaps and id rather not use uboot. System is working with edk2 and nixos.

Long story short, will this software allow me to figure out what is running in the manufacturer’s kernel and port it over?

Oh wow this is a fantastic write up! I really appreciate the effort you put into this. You’ve certainly given me lots to ponder over. I wonder if there is some credence to the humidity issue. Id have to do some digging on when the issue occured and what the conditions were like but some of the locations do get humid.

If you run systemctl reboot on a non-vm it will actually power cycle the system and cause it to go back through the BIOS and then the bootloader. Using systemctl kexec allows you to “restart” the computer without having to go all the way back through the full boot process.

In the case of a VM, some are setup to do this behind the scenes. For example, virt-manager allows for direct kernel booting. If you look in the options there will be a path to the kernel. If its not setup that way, then the VM still has a bootloader. In that case, restarting the VM with kexec will allow for a faster reboot since the bootloader is skipped completely.

Oh that sounds like a nightmare lol how did you even realize it was the office chair?

Yeah, unfortunately thats how I started to pin it down to that pci multiport serial card. Only sometimes if you unplug that cable does the system turn back on. Oddly, removing the cable doesnt always solve the problem. Sometimes the system will boot right back up and everything works just fine. Other times it will turn on, but windows will throw a driver error on the serial card.

The common factor tho, is that when they computer is shipped back, it will start working again. Very frustrating haha I appreciate the response as well!

Ooooo now this is something!! Ive always had a hunch that the way power is being injected into the motor was causing the issue. The serial device is connected by a DB9 port. The RS485 signal A, B and ground then gets accompanied by power to drive the motor. The serial port from the computer goes into this power injecting box and then the box goes to the moto and controllerr.

The grounds should be connected correctly. But now youve got me thinking about these boxes. Modifications have been .are to them overtime, so its totally plausible that something in there is causing a surge to get back into the computer.

Thanks for the response!

So you can just run kexec if its installed on the distro. This tells the kernel to boot into another kernel. The reason to use it with systemctl is to properly shut down all the services running in userspace. That command will have systemd gracefully turn off all services and then the new kernel with whatever updates / modules can be loaded in a clean environment.

Its useful if say, you have a VM in a data center. Now most of them provide a web gui where you can turn your VM off and then on. But if you’re lazy like me and already remoted into the terminal lol

Should have been more clear about the remote part. The systems operate remotely from me, I can access them via the internet. The users need to use the screen to operate it. This is just a windows 11 computer after all.

As for the router information, thats part of the reason I know there is power to the entire thing. I can access the router page and see that the link speed was negotiated correctly, at 1gb per second. If they unplug the ethernet, the port reads disconnected.

But 0 packets are getting sent from the computer. I believe those are ARP, but the router page doesnt define it. Just has a table with packets in and packets out. Packets going in will usually have a couple from the router. Always 0 with packets coming out. Theres actually a ping function built into the router, and that doesnt respond at all.

BIOS is not setup during boot to use any sort of networking. No PXE boot or anything like that. On this particular motherboard, you have to enable the network stack, so I dont think its that. System is setup to always turn on when power is applied to bring all the other components online together.

Anyway, thanks for taking time out of your day to respond!

I hope it helps you someday! :)

Power to all components is provided through a dedicated power supply. If the computer was on, I would be able to get direct readout of voltage and amperage. As for the serial ports, some devices use RS232 and some use RS485.

The ground loop certainly seems to be the most plausible cause. And when its in the shop I’ve got exact replicas of the system. I just cant seem to replicate it no matter how hard I try.

For context, Ive stuck a system in a fridge to see if possibly cold temperatures correlate and was still unsuccessful. At this point I wonder if there is interference coming from an outside source and thats why I cant pin it down.

You’ve given me a lot to think about! I greatly appreciate the responses.

Okay?

sit there with a black screen after turning on and not reaching the windows bootloader

Were you able to access the BIOS? We’re unable to access the bios when the computer stops working.

Also, even more frustering, we have a dedicated power supply to run the whole operation. If the system was able to turn on, I could read the voltages and amps going into the system. Weve swapped out the power supplies as well but that doesnt seem to resolve the issue.

Now that is an interesting idea. I cant go into to much detail about the exact components but this particular port drives a DC motor. Power is injected to drive the motor.

Tbh, im not very familiar with ground loops. Have you had experiences with ground loops before?

I appreciate the quick response as well!

I dont mean to be rude but I dont think thats relevant without doxxing myself. You can look at my post history to know that I’m in the US and my computers are as well. They are far enough that I cannot travel to them.

I think the command “systemctl kexec” would like to have a word. Great command to know if you have a VM on a system you dont manage / share with others.

Woah woah… is there someplace in the event logs where this would show? Does this mean that you cannot run a windows computer headless?

Bless your heart

I appreciate the sentiment, people being nice to eachother should always be encouraged. But thanking people always seemed odd to me. I drank a lot. :(

But Granny Smith Apple.

Thankfully, I’m doing better now :)

Theres a couple of mistakes there. For example, a Bronze star would be above the Navy Marine Corps Achivement ribbon since its a much more prestigious medal. I cant tell what the devices are but this is the stack.

Row 1

1. Navy Marine Corps Achievement Ribbon

Row 2

1. Navy Marine Corps Combat Action Ribbon
2. Navy Marine Corps Presidential Unit Citation Ribbon
3. Marine Corps Good Conduct Ribbon

Row 3

1. National Defense Service Ribbon
2. Iraq Campaign Ribbon
3. Global War on Terrorism Expeditionary Ribbon

Row 4

1. Global War on Terrorism Service Ribbon
2. Humanitarian Service Ribbon
3. Navy Sea Service Deployment Ribbon

Source: Eaten a couple crayons.