The unit started up just fine on reboot, however the background was changed from the Apollo background to an Ubuntu desktop background, and my miner for the full unit was no longer showing up in the dashboard as a miner (the 2 standard units were still showing up and mining just fine and mining on boot).
I don't know what went wrong with your flashing of the SD card.
Interesting that the 2 standard units were still mining after the Ubuntu update, I wonder how that works.
Have you put the nvme drive back in?
I would try to save the blockchain data in a new folder inside the Bitcoin folder on the nvme drive and try to boot with the nvme in the Apollo.
If that does not work, try etching the SD card again and double check that you have used the correct version. I found the instructions quite confusing and I used the images of the Orange Pi rather than the numbers to identify the correct image version for my Apollo.