Hello. I've flashed custom ROM RCMix3d and I would like to return to the stock one. I've used "fastboot oem lock" and now see "RELOCKED" sign seems that I can flash Official RUU. I've already tried to flash some and always got 131 error that means I have wrong region and can't flash this RUU. How can I identify my XL's region? When I can get original RUU for my XL and flash stock ROM?