You may try, but @Suren and me have tested a period and the dronehacks software isnt detecting the rcpro2 - you will get an error. So at the moment, downgrading is not possible.
But feel free to test and share your results.
I updated the Fly app on the RC Pro 2 to V1.17.0 and 4G still works. I don't want to risk trying updating to the RC newer FW because I tried Drone Hacks and the RC is not recognised at all. So far it works so will leave it as that until it's...