Linux v4l2 driver for Bt8x8 cards

Hi,
I'm working with a multiple-card/camera vision system under linux using 878-based cards. I have six cards, three older flyvideo 98 bt878-based cards and three newer flyvideo 98 fusion 878a-based cards. I eventually wish to get all six working simultaneously, but that's not my problem. my problem is that the older cards work fine, but the newer fusion 878a-based cards don't. i'm only using one card at a time now, so it's not any sort of overload issue. the cards themselves are ok (i think), as i've tested them under windows, and they work fine there. under linux, i get garbled images with the new cards. i'm using a simple pattern generator through the rca port for testing (checkerboard/colour-bar patterns and such). There is an image, and it's recognisable, but it is definitely not right. i'm using the pal colour system. any tips/hints/solutions? If you need more details, please ask.

Thanks in advance.
Des.