Invalid BS_jmpBoot in boot block.... What is that?

[raptorsoft2000]

Hey, I'm not sure what I did to my main disk to screw it up, but now I can't install Snow Leopard and I get this error when trying to verify that disk. Thanks for any help!




Verifying volume “disk3s3”
** /dev/disk3s3
Invalid BS_jmpBoot in boot block: d8a8e1
Error: Filesystem verify or repair failed.
Verify and Repair volume “disk3s3”
** /dev/disk3s3
Invalid BS_jmpBoot in boot block: d8a8e1
Error: Filesystem verify or repair failed.

 

[wrldwzrd89]

BS_jmpBoot, as far as I can tell, is a Boot Sector (BS) structure that tells the low-level firmware bits of the operating system where to jump to in order to load the operating system (or systems, if more than one is installed). If this gets corrupted, the computer will be unable to boot normally from the internal disk. Furthermore, Disk Utility cannot fix this error if it finds it, as you've discovered.

 

[raptorsoft2000]

Could it be caused by my installing rEFIt?? http://refit.sourceforge.net/
I installed that many years ago to dual boot windows which I really don't use and I'd like to get it off but don't know how!