I will try downgrading u-boot next once I find the older package somewhere. Kernel does not seem to be the cause given that it has been working fine with both my own build 6.6.122 and 6.6.128 before and rolling back not helping. New device is something I had on my mind for a while. But given the RAM and SSD prices these days, I do not really want to overspend. Not to mention that the SBC landscape has not been that great lately when it comes to compact NAS offerings. HC4 is five years old at this point. Many even recommend N100 but this is a whole different size category.

I would not be surprised if there has always been a HW initialization issue. It is just that now with newer Linux (whole systemd stuff etc) you hit this problem. I always liked this HC1, but it is not even on Odroid WiKi anymore. You might need to focus on version/build of U-Boot in combination with kernel and DTB. I have some examples (Rockchip based SBC's) were it is make-or-break, e.g. if I just take latest U-Boot whole system / use-case is useless / gone. So I need to stick to legacy U-Boot or just buy other HW/platform.

This could be, but something has changed and is now triggering this behaviour. Warm reboots have been working fine for years.

Is the much trouble USB-SATA chip, I have it as 'cable', but unused as it at least fails with RPI4 when SSD. It looks like a sequencing/timing issue. You can treat it like external maybe and/or reset the USB device node. That usually works for various USB connected HW that fails at boot but when Linux/platform fully up and running, a reset then somehow avoids timing issues.

Other packages upgraded by unattended-upgrades: Start-Date: 2026-03-15 10:51:39 Commandline: apt upgrade Requested-By: julas (1000) Upgrade: linux-base:armhf (4.12~bpo12+1, 4.12.1~bpo12+1) End-Date: 2026-03-15 10:51:51 Start-Date: 2026-03-16 06:20:00 Commandline: /usr/bin/unattended-upgrade Upgrade: linux-image-current-odroidxu4:armhf (25.11.2.3, 26.2.1) End-Date: 2026-03-16 06:21:56 Start-Date: 2026-03-16 06:22:47 Commandline: /usr/bin/unattended-upgrade Upgrade: base-files:armhf (25.11.2-12.4+deb12u12-bookworm, 26.2.1-12.4+deb12u13-bookworm), armbian-bsp-cli-odroidxu4-current:armhf (25.11.2, 26.2.1) End-Date: 2026-03-16 06:23:48 Start-Date: 2026-03-16 06:24:54 Commandline: /usr/bin/unattended-upgrade Upgrade: armbian-firmware:armhf (25.11.2, 26.2.1) End-Date: 2026-03-16 06:26:03 Start-Date: 2026-03-16 06:26:48 Commandline: /usr/bin/unattended-upgrade Upgrade: linux-dtb-current-odroidxu4:armhf (25.11.2.3, 26.2.1) End-Date: 2026-03-16 06:26:52 Start-Date: 2026-03-16 06:27:35 Commandline: /usr/bin/unattended-upgrade Upgrade: linux-u-boot-odroidxu4-current:armhf (25.11.2, 26.2.1) End-Date: 2026-03-16 06:27:37 Unfortunately, the previous versions seem to be gone from the repos. Is there any way of getting these back?