[0.235083] cma: cma_alloc: alloc failed, req-size: 2025 pages, ret: -12

Were you saying that this error shows up as you look at the console as the Pi boots up or were you saying the Magni is non operational after the upgrade?

I have not looked for this specific error on the console as i boot up headless.

I have done the full clean image up through upgrade ok and results are seen on a posting to another thread: Apt-get update/upgrade bricks Linux