[arch-general] What changed dual-boot grub definition (hd0, 0) -> (hd0, 1)

[Jan Steffens]

On Mon, Mar 18, 2013 at 3:55 PM, David C. Rankin
<drankinatty at suddenlinkmail.com> wrote:
> All,
>
>   Just a note. After working through the update that brought in systemd, a final
> issue is that somehow the drive designation for grub (legacy) for the windows
> partition was changed from (hd0,0) to (hd0,1). This box is a simple old dell box
> with a single 500G drive. Windows has 80G and the rest in Arch. The dual boot
> for windows definition in grub menu.lst has always been:
>
> title Windows
> rootnoverify (hd0,0)
> makeactive
> chainloader +1
>
>   'cat /proc/partitions' showed sda and then sda2 as the first primary
> partition. sda1 was no longer created by the system. Is there some reason that
> sda1 would be completely missing on the system where it had always been there
> before? This required the corresponding change of the menu.lst definition to:
>
> title Windows
> rootnoverify (hd0,1)
> makeactive
> chainloader +1
>
>   While the fix is simple, what caused the loss of sda1 in the first place?
> This box has booted Arch and then XP as (hd0,0) since 2009. Now it requires
> (hd0,1). Is this related to the same udev issue that caused eth0 -> enp2s0? If
> so, can I rely on it staying sda2 going forward or do I need another softlink in
> /etc/udev/rules.d to make it so?

Since both grub and linux (which are independent) show the issue,
something altered your disk's partition table, moving partition 1
(which grub calls 0) to partition 2 (which grub calls 1). You can read
the table(s) with "sfdisk -l". This has nothing to do with systemd or
udev.