I just had several problems for install any rom caming from the CM12.1: it returns me error 7 and the recovery can't flash the system image with error "unable to mount /system" and then errors such like "failed to extract dir from system to /system". I solve that problems by check and unckeck the "read only system" option, after one full day of change recoveries, made restores from MiFlash and other stuff. I'm gonna ask to the italian forum of Meizu what changes there are between this two kinds of rom, but for this day (and for undefined weeks) I' don't think to change my ROM, after this hell... I'll update you when I'm gonna to install this FlyMe. Thanks you for help! See you soon!