Warning: One wrong hex edit can hard-brick your phone.
This is the safest method for beginners. Octoplus supports LG G8 (models LM-G710, LM-G810, LM-G820, LM-G850). lg g8 imei repair
: A standard LG flashing tool that, when configured with specific .dll files and used in PDM (Product Data Management) mode, can rewrite the IMEI to the device's NVRAM. Warning: One wrong hex edit can hard-brick your phone