Made by 303 and jedimstr from bitcointalk.org

To update firmware on Mac:
1. short the jumpers on your bi•fury and plug it in
2. Close all finder windows (just to be safe)
3. Open terminal, cd /Volumes/CRP\ DISABLD/
4. rm firmware.bin
5. curl -R -O --ssl http://c-scape.nl/bi-fury/firmware.bin (this downloads the firmware and leaves the modified date intact)
6. type diskutil list and note which disk# is used by CRP DISABLD, let's call this N (as in "diskN")
7. diskutil unmountDisk /dev/diskN where N is that # you just recorded
8. unplug and plug back in. The light will turn on then off again

To get it running in cgminer now:
1. sudo cgminer -o yourpool -u username -p pass — that's all, and thanks jedimstr for the sudo tip!

Here's why downloading firmware on a mac and dragging it to the drive doesn't work:

Mac OS X / Chrome download does two things that mess with the file:
1. Mac OS X adds extended attributes (xattr list firmware.bin) to the file, one of which is a quarantine check.
2. Mac OS X modifies the date of the file (I'm not sure if this messes with it, but everything seems to go smoothly when I adjust for this with -R in curl)

What was happening was that the device didn't like this file and would overwrite it with its default firmware.bin, throwing us in a loop.