I've used faircrack on my v47 kernel and it seems to be working, although I haven't got as far as injecting packets yet. What I will say though is that it absolutely HAMMERS my battery. My phone was red-hot and the battery went from full to red in under 4 hours whilst sniffing a nearby signal. Even when I disabled injection and monitor modes it was still eating it faster than normal. This was on normal profile, no overclocking or undervolting at all.