I have been working with Fusion 10 for more than 5 years, main recorder .
Please check the Primary should be 32( or16) GB but must be 133x speed !!!as per mirror CF you can try any CF Transcend , Delkin, 8, 16,32,64
at higher speeds, that will not change the speed of mirroring. Fusion 10 will not accept any higher speed for Primary Card due to the speed of DSP board of the Fusion as well as all Deva family products. Further more you cannot swamp primary with mirror.
Please try to use a new mirror card , FAT 32 format on the recorder, and see .
The only issues I have had so far were with the mirror cards due to our DIT transfer guys.
I am pretty sure you will be fine once checking all this facts, as well if you reboot the machine will reboot with firewire on , so restart with the internal disc( CF card primary).