So if you take a macbook air with soldered-on ram, which was available in 2 configurations of 16GB and 32GB, those two configs are baked into the bios, you just need the correct density, speed, and CAS latency to go from 16 to 32.

But if you stray from what’s in the firmware/bios, you’ll need to figure out how to get the ram recognized so it can be used.

In a raspberry pi, the known configs are in the firmware, so resellers were taking cheap low-ram pis, replacing the ram with double-density and selling them for a big markup from their cost, but lower than a retail RPI.

The new policy would force these resellers to mod the bios to keep doing it.