move boot SD from Pi4 to Pi400 - not booting to OMV

I have a Pi4 running OMV from an SD card and data stored on an SSD.

As a backup ( in case of pi4 failure ), I want to be able to move the SD and SSD from the Pi4 to a Pi400.

The Pi400 is currently being used with no SD card, OS and data on an SSD, and it boots to a linux desktop.

Moved the SD and SSD from the Pi4 to Pi400, and it did not boot to OMV.

Is there something that I would need to change in the raspi-config to make it boot / run OMV ?

also, having just read that the raspi-config tool modifies files on the boot sd card, I don't understand why, moving the SD and SSD from the Pi4 to the Pi400, doesn't boot exactly the same as it does on the Pi4

something on the Pi400 is preventing it from booting from the SD card.

The current setup on the Pi400 is the OS and data partition running on the same SSD.

So I'm starting to think that I should :

1. Clone my SD to a new SSD

2. Create a Primary ext4 partition on the remainder of the new SSD

3. Clone the Partition from my existing data ssd, to the new partition.

4. Boot from the new ssd, and relink all the shares / smb shares / docker containers, etc to the new ssd.

Anyone see any parts of this process that won't work ?

Also, if I am able to change the UUID and PARTUUID to the same values as the original, would I then need to relink everything ?

Quote from Soma

Run raspi-config and make the bootloader to use the STABLE version.

only options I see there are :

E1 Latest Use the latest bootloader image

E2 Default Use the factory default bootloader image

I was hoping the proposed process would do away with the SD card, which from what I've read, wouldn't be a bad thing as well

Quote from Soma

There should be there, also something like "Boot Order" or something similar.

B1 SD Card Boot Boot from SD Card before trying NVMe and then USB (RECOMMENDED)

B2 NVMe/USB Boot Boot from NVMe before trying USB and then SD Card

B3 Network Boot Boot from Network unless override by SD Card

Quote from Soma

Select this one.

Thanks. will try this in the morning. Also still keen to get the OS and data partitions on to the same ssd