It's not as easy as just writing a bit of code and making it compatible with 5.1. They'd need an entirely new exploit that no one has ever found yet.If the firmware spoofing can be easily blocked in future releases, doesn't that seem a bit worrisome for 5.1/6.1 support? Seeing as how they could have kept the spoof exploit under wraps and simply updated the supported firmwares for the same effect, now it'll be blocked needlessly instead (unless we never see 5.1 support).
And if firmware spoofing would be blocked in future releases, it wouldn't be for 5.1 or 6.1, it'd be for 6.3, 7.0, etc. So even if they release a patch that supports 5.1 and 6.1, it wouldn't be blocked.