> On Jul 17, 2015, at 1:24 PM, Mark Stodola <[log in to unmask]> wrote:
> 
> On 07/17/2015 12:56 PM, Larry Linder wrote:
>> 4.  We need a way to gracefully remove SL 7.1 if we can't then we will have to
>> do a low level format on disk.
>> One of the guys suggested that we take the disk out and put it on fence post
>> in south forty and he would loan me his twelve Gage.  Just because a low
>> level format takes so much time.
> 
> Low level formatting is a bit extreme.  If the install truly did do something to the disk, wiping out the first 512 bytes or so of the disk with 'dd' is usually adequate to recover.  This should wipe the MBR and partition table.
> 
> dd if=/dev/zero of=/dev/sda bs=512 count=1
> (or whatever the raw disk node is)
> 


There might be additional steps if the disk is GPT, since there is a secondary GPT header at the end of the disk. 

If that’s the case, use parted or seek to the end of the disk and dd zeroes onto the last 512 bytes as well. 

Cheers,
Lincoln