Recently the new iOS 8.3 has been released. Our customers informed us about the fact that the previous patches for 2G/3G switching and not working anymore.
We are not sure as this point that iOS 8.3 will support such patches so we advise all customers not to update to iOS 8.3 because of this issue unless their devices are already working without using this patch method.
Also a lot of customer seems did not knew that iPhone 6/6P can be also unlocked using V7 firmware version (except Sprint). In case you have not tried it, you can try to unlock your iPhone 6/6p using this firmware.