assuming it is a sil3112 or sil 3512 based card, you could try flasing it using the wibietech flasher, but replacing the included firmware with the on for your card

As long as the card can be seen by the system (but it dosen't have to work) it will flash the card, i used this to flash the sonnet firmware to a 3112 card with a larger flash chip installed (pulled of a pc mb, so it would have a seemingly junk firmware to the card)

It however, dose flash compleatley blindly, doing no checks to the firmware, so make sure you have the right one!