So now, you phone is booting or still FC?i was on cm 10.2
then i did all wipes and then erased boot and flashed boot with fastboot then erased system and data and cache whit it and finally flashed cm 12.1.
If still FC, make a clean install:
delete and create new partitions on SD card/
then install clean 4.0.4-587, and then follow throw an install guide in CM post.
This should work fine (i always do a clean install before flashing a new ROM).