I tried to downgrade to 6.18, unfortunately it froze during the process, which left the kernel and boot loader in an incomplete state. I have decided to re-image the whole thing with 6.18.x and for now it appears to be stable again.

Your previous post reminded me that the board supplier changed the BOM of the ODROID-N2+ by using a different SPI flash vendor. He hacked the support for it into his legacy firmware build without making any further note about it. It took some effort of reverse engineering to figure that out. Mainline hasn't picked up this additional driver activation to this day, but I still keep it in my builds anyway. In my latest build for the ODROID-HC4, I also included this driver to see if they might have gone about it in the same way. But your confirmation shows that this is probably not the case. Since I don't have an ODROId-HC4 with the behavior you described on hand, I can't analyze any further what the cause of it is. These days, I also mostly avoid devices with Amlogic SoCs because of their strict closed-source policy and lack of mainline support. And the board manufacturer isn't much more helpful on this point either. Devices powered by Rockchip are much more appealing objects. So you have to help yourself if you want to find a solution.

These most recent edge updates for K1 based boards are really great! With all this mainline additions of kernel 7.2 it's finally becoming a trustworthy clean alternative to outdated vendor images. At least for headless micro server usage everything is now already provided by mainline code (e.g. temperature and CPU frequency control are indispensable for serious work on this board!) Only WiFi and BT still don't work out of the box. I personally would prefer utilizing mainline brcmfmac drivers instead of fighting with all those unmaintainable bmcdhd patches. That's working for other boards with AP6256 modules as well.

OK I see: # dmesg | grep watchdog [ 0.462093] sunxi-wdt 1c20c90.watchdog: Watchdog enabled (timeout=16 sec, nowayout=0) That would mean study 'bark' or so, forgot most of it. I guess the board should restart if IPv6 LL connection is not there for more than 1 minute or so, but in relation to NAS makes then only sense if I move from NBD to iSCSI or so.

The forum returned 'nginx bad gateway' but I see draft of may message is still there. In the meantime, I did a simple 'apt update && apt full-upgrade && reboot' and now I have: U-Boot SPL 2024.01-armbian-2024.01-S866c-P7738-Hb9d3-Vf23c-Bb703-R448a (Jun 21 2025 - 02:53:13 +0000) Kernel: Linux 6.18.35-current-sunxi I might look into HW watchdog things, no clue if it is there and able to work, but used it successfully for Raspberrypi4 to workaround USB3 lockups/crashes.