Free patch utility for disk image files

[pupkin]

Hello,

I want to distribute images from CompactFlash cards. For the updates I'd like to create only patches. I've already tried PatchWise 3 but it crashes diffing 500Mb images. I'm looking for a free robust utility for Windows. Does anybody have an idea?

Thanks in advance

[pupkin]

I have finally found a suitable one:
xdelta http://xdelta.org/