Do you know which class makes the processor registers directly available to developers using TinyCLR OS.
Take a look at the methods available in System.Runtime.InteropServices.Marshal. They can be used to read and write arbitrary memory addresses.
Would I be able to use System.Runtime.InteropServices.Marshal to write and read data to the internal EEPROM on the G120 module?
Marshal just reads/writes from/to a pointer. So if you could interact with the EEPROM in native code via only pointers, then you can through Marshal as well. We have not tested it ourselves.
Is that currently the only way that I would be access the processor’s built in EEPROM?
You could also write a native interop driver yourself. But both require you knowing how the EEPROM on the processor works.