20h change on drive

I have a drive that almost every other bit on the drive has the hex value on the drive increased by 20h. I can edit the drive values in the boot sector to get it to boot but it is too much work to continue this process for the whole drive. What can cause this and can I use a software tool to fix it? Some say that it is a broken pin and others say that it is too consistant to be a hardware issue.