You need to use the WinLoader application to change the firmware of the device, however, it has been reported that downgrading is not possible no matter solution you choose to try. Acquire a new version of WinLoader and then attempt a possible downgrade, instead, downgrade successively, meaning you should downgrade from 2.86 to the available 2.84 and so on. Apply all the firmware versions in reversed order. Nobody suggested this, but I was succeeded to do that for other devices as well.
