Not loading on new hardware

It's simply a BIOS configuration issue preventing you from booting from your system drive. You'll likely need to check your Secure Boot options and configure either UEFI or Legacy mode, depending on how you initially installed Debian on that drive.

There are probably some other settings on that motherboard that you may have overlooked.

On your previous motherboard, was the boot configured in UEFI mode? Or in legacy mode?

This is what ChatGPT replied to me, maybe it will help you.

Quote

Yes, what you mentioned about Secure Boot and UEFI/Legacy Boot is very common when changing motherboards and CPUs, especially if the CPU generation has also changed (from Haswell/G3260 to Alder Lake/i3-12100). But there are a few additional points that can help the user before considering a complete reinstallation:

1. Check the operating system's boot type

If the disk with OMV was installed in Legacy/BIOS mode, and the new motherboard is configured for UEFI, it won't boot.

Solution: Configure the motherboard to Legacy/CSM or, if you want to keep UEFI, convert the disk to GPT/UEFI (more complicated).

2. Temporarily disable Secure Boot

On newer motherboards, Secure Boot can prevent an "unsigned" Linux kernel from booting.

It's recommended to disable it until the system boots and then consider enabling it again.

3. Check kernel compatibility

OMV6 (based on Debian 11) supports modern processors, but some B660 motherboards with Alder Lake require a kernel version 5.15 or higher to boot correctly.

If the kernel version on the disk is older, the system may not boot.

Possible solution: Boot from a compatible Debian LiveCD/USB, mount the disk, and update the kernel before booting again.

4. Connect only essential drives

Disconnecting other drives can prevent boot conflicts and make it easier for OMV to detect the drive.

5. Check the SATA/NVMe configuration

Some newer motherboards require changing the SATA mode from IDE to AHCI, especially if the drive is SATA.

6. Using initramfs or repairing GRUB

If OMV doesn't boot, sometimes reinstalling GRUB from a Live USB is sufficient.

Code

mount /dev/sdXn /mnt      # partición root
mount --bind /dev /mnt/dev
mount --bind /proc /mnt/proc
mount --bind /sys /mnt/sys
chroot /mnt
update-grub
grub-install /dev/sdX
exit
reboot

This updates GRUB with the new motherboard and CPU.

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On an Asus motherboard I bought a little over a year ago, enabling Legacy mode requires adding a BIOS password. Perhaps this is also the case with this motherboard.

Secure boot is disabled? What are the options under Boot Device Control?