Grub2's chainloader cannot load extlinux (syslinux)

[gutschke]

As reported on the Grub developer's mailing list (http://osdir.com/ml/grub-devel-gnu/2009-07/msg00387.html ), Grub 2 has a bug that prevents it from reporting sufficient information about the partition table when chainloading other boot loaders.

Among others, this affects users who want to chainload extlinux (part of the syslinux package) from Grub2. I believe, this refers to the same bug that was discussed by the Syslinux author at http://syslinux.zytor.com/archives/2006-October/007527.html

I forward-ported the patch from the Grub mailing list, and it fixes the problem for me. The patch is attached to this bug report.

[gutschke (markus+launchpad)]

BTW, the reason I need this feature is so that I always have quick access to an emergency rescue system. I copied the contents of the Ubuntu installation DVD into /boot/rescue and then installed extlinux to boot this system. Extlinux is the preferable option as the installation DVD already uses isolinux which can trivially be converted to extlinux. In fact, I am surprised the installation disk doesn't come with instructions on how to do this.

I then tell Grub2 to add a menu entry to the boot entry which lets me start the rescue system instead of going through the normal boot process.

This comes in handy on a laptop as I am not normally in the habit of taking a rescue disk with me -- in fact, I don't even normally take the DVD drive with me. But always having access to a rescue disk is definitely very reassuring.

[Geert Altena (ge2rt)]

Could this be related, if not the same issue, to the various other bugs around here where Grub2 fails to chainload a second bootloader that is in the MBR of another physical disk (HDD or DVD). I'm experiencing this with XP on the second HDD, as are multiple other people. Some looking around shows that there is much confusion on this issue...

[angelo75 (angelo75)]

In addition to Geert Altena:

Is there a connection to bug 484102??

https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/484102

[Marcus Tomlinson (marcustomlinson)]

This release of Ubuntu is no longer receiving maintenance updates. If this is still an issue on a maintained version of Ubuntu please let us know.

[Launchpad Janitor (janitor)]

[Expired for grub2 (Ubuntu) because there has been no activity for 60 days.]