While I sit waiting for my Stellarmate Pro to be delivered(even the manufacturer not giving a firm date at this point), I find myself bothered by the thought that all my problems, as detailed in my "bad-to-worse" topic, may not be due to my favorite suspect, my Raspberry Pi, at all. Maybe it's the camera. Maybe it's the cabling. Maybe it's who knows what. How does one TEST a Raspberry Pi? Are there test suites of memory etc. that can be run from Astroarch? Are there ways to test the USB connections on the Pi? Grateful for any help anyone can provide. It occurs that this may be of use to others in my predicament.

hey Steve, this is a complex topic with rather "it depends" answers. I'll try to share my very own experience tho

I know Matteo knows some tools to test disk performance for example, not sure about the name. You can copy files over your local network and check the speed is what you expected to be sure your network controller is ok.
USB hardware is either 0 or 1, it works or it doesn't - while it may be the case some time a connector is working partially I believe the kernel will barf loudly about this fact - "sudo dmesg -w" will tell you a lot of good stories about all connected stuff
even for external hardware is not easy to tell, I have seen myself UNDOCUMENTED things from ZWO that lead me to spent 3 days wondering wtf was wrong with my program and I discovered only lately after I was finally able to reproduce the problem with 100% accuracy they they somehow forget to tell a cooled camera which is not cooled is keen to fail exposures if not fed a 12V anyway.

OS differences
While the phrase "it works on Windows/NINA/put here whatever but not on Linux" is most often than not a good sign that software is broken, it's not always the case as the manufacturers SDK themselves are very different in nature the way the talk to devices because of platform differences.

Works on mine
same as the OS, while it may be not correct for 100% of the cases, if few people have the same setup and things work, it's a decent sign your hardware may be broken.

I know, this is not a decent answer and probably not the one you wanted but it's also incredibly hard to find the exact issue one could have because sometimes (not telling it's your case) in the rush to test potential fixes found on the internet the user may change something on the system itself.

What I may suggest for your case:
have a ram test with memtest (sudo pacman -S memtest)
fsck to check the state of your media (usb/sd)
firing up a terminal and run sudo dmesg -w and observe what it spits while you attach and operate your devices
change cabling and see if that cahnegs anything
use a powerd USB hub to see if voltage is more stable

To your specific problem

the green balance comes from the WB values, I never had issues with light frames but I had to throw away calibration frames because of that and I moved to 50/50 and all disappeared
the ASI_GENERIC_ERROR comes straight from the ZWO SDK and is, well, generic meaning "dunno" but, and please TAKE THE FOLLOWING JUST AS MY PERSONAL OPINION:
you said you don't think is the power, I may try to convince you it may be the power, battery have huge issues to stabilize the output voltage and if it is too low the camera won't work properly - NB the amperage may still be fine but your voltage may be just too low for the camera to work, especially if you use the PI with all equipment attached, additionally, the pi USB ports, if I remember correctly, may output a max V each but also a max as a whole and here I have seen people in the past having a ton of troubles because of that - source => myself and banging the head against walls

it could still be the pi, and if you have a friend who owns one you can easily exclude/confirm if it's a broader issue but if I had to bet, I'd point my finger at power management

Hey, Mattia:

I know, this is not a decent answer and probably not the one you wanted

Not at all, bro! I can't thank you enough for your detailed explanation, it provides me with the right way to think about this.

A few further points if you will:

1. The green balance thing is the one problem I DID manage to get a handle on, with the white balance settings that I previously didn't know what to do with.

2. As for investigating the power produced by my power supply, I am going to take that seriously and have ordered a multimeter to test it. Only, how would I actually test it? For example, the cable plug into my mount is covered, so I'm not sure where I'd connect the probes. Or can I test at the power supply itself? Wouldn't the current depend on the amount drawn by the equipment?

3. as for a powered usb hub Isn't that what the Stellarmate Pro provides?

Hello Steve,

Mattia is absolutely right in these comments.

To test and/or resolve certain problems, you must first keep it simple by breaking down the devices.

For the pi, I think it's a very solid basic device. If the voltage is good 5v, normally the amperage adapts to the needs of the pi. The only thing to check is to have the right battery, depending on a pi4 (3A) or a pi5 (5A). The only real issue is the sd card.

The errors you encountered are either an incorrect configuration (ex: green balance), or a device that is not working correctly (ex: your camera not connecting).

The logs made it possible to resolve the green background issue. For the camera, it should be the same with all logs and how it is plugged in/powered. There is little chance that the issue comes from the pi.

Is this a cooled camera? Do you use an external battery? Have you connected the camera and the mount to the same power ?
Have you checked all logs to determine the error? Did you have any problems other than the camera?

Don't compare the pi to the Stellarmate. Stellarmate is a "pi" + a card with all the necessary power supplies (camera, heating strips, etc.) + a dedicated OS. It is an Asiair but can be used with any brand of device.

I use KDiskMarkHere some screenshots as reference with cheap SD and with an NVMe using Pi 5 with PiMoroni Base:

I’ts not easy using a multimeter to inspect it (easier with an oscilloscope). If your multimeter has a current clamp and the options to keep memorized min and max, you can inspect if the peak can be managed by power supply.
What version of Raspberry Pi do you have? The Pi 5 is finicky regarding the power supply. I tried different power supplies but to maintain a stable 5.1V during the boot is not easy (Pi 5 power supply specs)
An easy way to understand if the Pi gets the right voltage, is to boot using Pi OS. You get an alert about power issue.
In past I had many issues connecting devices to the Raspberry USB ports with Astroberry. All solved connecting to the USB port a power USB hub (as Mattia told): you get the current from external USB cable, not from Pi.

Thanks, but I don't know what an NVMe is nor do I know what PiMoroni base is. My pi is a 4. I tried to get KDiskMark to show you what it produces but the install failed.

Try again the server is probably overloaded

A 404 may also mean the pacman cache wants to pull a package which is not hosted anymore (newer version released) use -Sy or - Syu instead of -S only