Just bought a used ES2. It has FW 1.5.0
I want to patch it to go 20 km/h max for legal reasons.
As it is not possible to patch 1.5.0, can I downgrade a patch to 1.3.9 on my 1.5.0 instead, or will that not work?
What do I sacrifice?
Only want to change max speed.

Thnx!