Network locking is never affected by firmware flashing. Network locks are protected using a completely different part of the phone. Never got around to seeing how phones do it. But yeah, flashing a different "brand" of firmware only changes bloat and bug fixes (assuming different versions).
Ok so I live in Japan and my ROM version, unlike the rest of the world apparently,
doesn't begin with a 'G920'
Mine is SCV31KDU1AOE1
Now since its firemware isn't in this thread and seemingly nowhere on the internet,
does this mean if I flash a custom ROM I have no way of going back and thus maybe shouldn't?