8" drives and Compaticard / Uniform

I can't imagine what's stopping you from reading the diskette, except that I don't believe it helps you to have so many drive types present on the CompatiCard. Having sold mine, I can't reproduce your results. However, it's not a bad idea to read the first two tracks into memory if you can read anything at all, then try to correlate it with a known-good image of the BDOS and CCP. That will tell you about the sector skewing, etc. Some vendors number the sectors sequentially yet read them out of numerical sequence, in order to improve performance. Others write the sector numbers in the optimal arrangement, which is not in sequence from 0. One other gotcha is that some systems require that the first two tracks on the bootable diskette be single density, yet the rest can be double density.