There was discussion on this in Github, but recently there's little progress.
People there figured out which packets need to be sent to trigger the change, but didn't prepared a complete tool which automates that.
They also didn't considered if/when the drone sends similar packets by itself and overwrite the change.
The packet needs to have cmdset=9,cmd=06; details are on github.
Besides that, there are many fake recipes on the net, which rarely get debunked as not many people have (and are able to correctly use) RF power meter. There also seem to be a placebo effect - even methods which got debunked have still their followers.