accidental fdisk -BI

Henrik W Lund henrik.w.lund at
Sun Oct 17 04:00:29 PDT 2004

Matt Juszczak wrote:
> I accidently did an accidental fdisk -BI on /dev/da0, which is where my 
> main freebsd root is.  I meant to do it on da1 but my twiddle fingers 
> typed 0 instead of 1.  I rebooted the box thinking I'd have to reinstall 
> (luckily my user data is on a different drive), but the box came back up 
> fine ... I was shocked.
> Can I continue to use it?  Did I just not mess anything up some how?  Or 
> have I messed something up secretly and even though the box runs fine a 
> reinstall should still occur?
> Thanks!
> -Matt

What you just did was zero out the bootcode portion of the MBR (which is 
fine if you don't multiboot) and initialize the partition table of the 
MBR to read just one FreeBSD slice covering the entire disk (also fine 
if you only had one FreeBSD partition there to begin with).

What this means is that any other slices you had on the disk will be 
gone. I don't know what disk layout you had, but something tells me that 
you may have erased /usr, /var and /tmp (if you used the default fdisk 
layout when installing FreeBSD, that is). I'm no expert, but I think 
this _can_ lead to complications.

Henrik W Lund

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