When someone works out the darn fex file.
Nowadays, you should just use a mainline linux kernel (with DT) rather than the old Allwinner kernel (with FEX). Of course, that just shifts the problem to "someone works out the darn DT file", but at least it's much better supported (and there's even an upcoming patch for that vanilla kernel which can finally lift the write speed limit on SATA from 50MB/s to 150MB/s or so).
Stefan