I'm sorry but, lmao, this is entertaining to read. The sd card is OBVIOUSLY corrupt, it even TELLS YOU THAT in what you posted. But you think what I am seeing should tell me it fubar. That fact that this configuration works perfectly for 6 or 7 other machines in this house long string of cat5 or cat6 cable seems to be blowing right on by. This can't be true for all 4 u-sd cards I''ve tried. The last 2 were brand new, even faster rated cards, but all are 128gig sandisk's 1: the image itself has a dos table, which doesn't work above 32gigs acc what I have read and this prevents mounting the written images for installation in a card reader, but the used partition is ext4, so it boots ok but takes a long time because the net failure blocks the boot for many minutes 2: so I back up to a 25_05 image, and at one time had it booting the 6_18 kernal, but still no net which is the original problem. ATM I am wasting my time on a 25_05 build image which is running just fine on another bpi-m5 driving a 3d printer about 10x faster than OOTB. So I'd suggest you pass this one off to someone who knows how to make a 50 line /etc/hosts file work without a dhcp because I'm doing it on 2 other wintel boxes, an rpi4b running bookworm and 3 bpi-m5's running noble on 3d printers. The best I can do is post a pix of the 'netplan status --all" screen and somebody tell me whats wrong instead of berating me for not running a dhcp server properly.

I'm sorry but, lmao, this is entertaining to read. The sd card is OBVIOUSLY corrupt, it even TELLS YOU THAT in what you posted. It's probably a good idea to go back to the basics and learn linux properly if you don't know what a msdos (MBR) partition table is. https://unix.stackexchange.com/questions/289389/what-are-the-differences-between-the-various-partition-tables As for how to NORMALLY SETUP A NETWORK, you can read my earlier responses, no host files on the devices, no hardcoded ip, just a correctly configured dhcp server that delivers the CORRECT IP:s to all devices. Then the dns server on the network (dnsmaq in this case) resolves desired domains to local ip:s. That way, there is NO NEED to do ANY CONFIG on the devices, it is all done on the entire network.

@Nick A Thank you, can you publish a server image for the Radxa A7Z with kernel 6.18?

If an pre-made image is not there, just DIY. https://docs.armbian.com/Developer-Guide_Build-Preparation/

I see. Well I can confirm my bootloader is very stable. I have been running it on two devices for a couple years now without any issues. It cannot hurt to flash it again (to rule out random bitflips), but if you are getting sporadic crashing no matter the kernel/OS it does start to indicate a hardware issue. I have a laptop that crashes sporadically but it isn't so bad that I cannot use it. I've run memtest on it countless times without issue, tried replacing RAM, etc. some devices really are just cursed for whatever reason unfortunately. In case it is helpful, you can find the config for the kernel I run on my devices here: https://github.com/bschnei/linux-a3700