That you have a backup of your original NVRAM/IMEI data, as flashing firmware can sometimes wipe these identifiers.
Before adding software logic, you must define hardware pins in the preloader-k80hd-bsp-fwv-512m
Some power management ICs (PMICs) use FWV to denote a factory-trimmed voltage window for overclocking the GPU to support HD playback at 60fps. That you have a backup of your original