Just a playful thought

I know nothing about differences between FW versions, specifically 4.82-4.86, but I still had a strange thought.

We all know that we need both a CEX and a DEX firmware file to make a REX CFW.

Couldn't it be possible to use the last available DEX (I guess it would need some edits and stuff) to make a custom REX FW, without the use of a later DEX FW? Or is the difference simply to great between versions?

Just a thought.