Anti RollBack with LG ota updates

This also applies to Lg G Flex 2,so I literally copy and paste it here

Quote:

This was not written anywhere specifically on the LG G4 forums that I could find. But every flash-addict needs to be warned. It is something you want to know before you continue tinkering. Several users (myself included) have made the unfortunate mistake of attempting to downgrade their bootstack (for various reasons) to a former version. DO NOT DO THIS (at least for the USA T-Mobile H811 version, and possibly other USA versions, per @autoprime)! It will result in a hard brick! Specifically, this results in the "Qualcomm QDLoader HS-USB port ( 9008 )" error. Connecting your phone to a PC will pop up with this active connection, but nothing else. There is no download mode. There is no publicly available fix as of yet. There are reports of this happening both through KDZ restore as well as flashing bootstack .zips. Yes, an official KDZ image can BRICK your USA phone, if you try to rollback. This is in stark contrast to other manufacturers (i.e. Samsung), where the attempt to flash an older bootloader/modem/radio will simply fail, but your phone is not bricked. I have conferred with @autoprime, who confirmed that with each OTA firmware release (on T-Mobile it was 10H, and now 10N), the version # increments. Flashing a lower version # will result in brick. I have searched far and wide for a DIY fix. Without the proper firmwares in the right format, as well as the right flashing software, your phone is done and must be sent in for LG repair.

OP
http://forum.xda-developers.com/g4/g...de-g4-t3197675