From the BIOS release notes:
- System BIOS can't be downgraded from R29 to the previous version.
Reading the thread, it sounds as though the fix back in 2011 was *updating* to BIOS 28, not trying to *downgrade* back to BIOS 28.
If you are using a sandy bridge processor, not an ivy bridge, you could do a BIOS recovery back to 35, then 33, then 29, but you would have to stop there. And it most likely wouldn't fix your issue anyway.
Have you tried updating the firmware on the controller, and disabling the board's onboard RAID?