Arduino Mega instead of UP! Plus 2 corrupted CPU

Hi,
I have UP! Plus 2 with corrupted CPU and i want to replace Arduino Mega with Marlin firmware instead of it.

At attachment, there is a photo of my CPU and Mainboard PCBs with model and version infos.
Could you share schematic and layout of CPU Board?

This may not be exactly what you’re looking for, but it seems TinyFab.xyz sells an alternate CPU for reasonably cheap ($65 shipped roughly) and it works with all open source software.