[ILUG] Doh - Partition Types

[David Neary]

Hi,

I'm surprised you didn't get an answer to this - but here goes.

You could try editting the partition table manually. You can boot linux,
so just take the first 512 bytes from each h/d (if you have extended
partitions you should be able to find them from the primary partitions),
open it up in a hex editor (like emacs in hexl mode, or whatever the
equivalent is in vi), and change those 0s to 83s. 

The format of a partition table is fairly simple - a boot program,
followed by some space, followed by 4x16 byte entries for the
partitions, followed by a disk ID (which, for me, has always been 55aa -
not sure why). The 16 bytes for the partition entry are:-

00 
bootable? 80-yes 00-no

01 02 03 
Start of partition (CHS in the part - not sure how this works in LBA)

04
Partition type (05-extended 06-fat16 83-Linux 82-Linux swap 85-Linux
extended)

05 06 07
Partition end

08 09 0a 0b
Partition start in LBA

0c 0d 0e 0f
Partition size in sectors

dd off the top 512 bytes from /dev/hd[abcd], edit them to get it right,
and dd them back on. Should work, although it's messy. Maybe someone
knows a cleaner way?

Cheers,
Dave.

"Breathnach, Proinnsias (Dublin)" wrote:
> 
> Anyone know how to reset the partition types from within Linux when the type
> was set to 0
> 
> <Scenario mode=Dumb_Thing_To_Do>
> Decided I had to reinstall NT (dualboot) for various reasons:
> Booted Linux (SuSE 6.4), set all linux partitions to type 0 (so as to avoid
> a problem with NT's loader/installer)
> Ran NT setup, all went well,
> Booted from a rescue CD ... Mounted all original partitions ok (inc the
> reiserFS one)
> opened fdisk .... couldn't see the partitions ...
> </Scenario>
> The kernel and filesystems see all the partitions, and can mount them, fdisk
> (and friends) don't, so I can't retype them.
> gpart sees the first few (smaller ext2 partitions) but doesn't recognise the
> reiserFS one, and overspecs the swap partition at the end of the disk
> 
> Anyone out there ... Something like this *always* happens just as I get the
> system into a usable state ...
> 
> P

-- 
		Dave Neary,
	Software engineer, Informix Dublin.
		Ireland.
	Phone: +353-1-409-1357