Change in loader or kernel: won't boot with kfreebsd in grub2

Juergen Lock nox at FreeBSD.ORG
Wed Aug 21 16:49:30 UTC 2013


On Tue, Aug 20, 2013 at 02:54:44PM -0700, Thomas Mueller wrote:
> This is what /cdrom/isolinux/isolinux.cfg shows for Super Grub2 Disk entry:
> 
> LABEL grubdisk
> MENU LABEL SGD: Super Grub2 Disk
> kernel memdisk
> append initrd=/bootdisk/grubdisk.img floppy raw
> 
> This is from the latest SysRescCD beta.
> 
> Now I wonder how or if one can access a CD or DVD from GRUB2.
> 
> GRUB2 has (hd0) (hd1) (fd0) but no (cd) or (cd0).
> 
Not sure about a physical cd but booting an iso should be possible
using either memdisk from grub2 like in the posting I linked,

	http://ubuntuforums.org/showthread.php?t=1549847&page=13&p=10818457#post10818457

_or_ also using grub2's own loopback command like described here:

	http://michael-prokop.at/blog/2009/05/25/boot-an-iso-via-grub2/

(but btw the super grub disk iso should also boot directly when dd'd
to an usb key, not only when burned to a cd/dvd.)

 It could only be that the partition table on your disk is somehow
messed up/has leftover data from a previous install that confused
loader and might confuse grub2 too so that it doesn't find the
FreeBSD install...

> I also wonder how or if one can boot a FreeBSD partition from GRUB2 or syslinux.
> 
 That's what super grub disk's autodetection should now detect
correctly, if you want to write a grub.cfg entry manually (or type
it live from a grub2 rescue shell) an example is also here:

	http://forums.freebsd.org/showthread.php?p=85122#post85122

but note as I said before if you want to boot a 9.1+ kernel directly
w/o loader you need a grub 2.00 version that has the patch mentioned
here:  (that's now in debian and in FreeBSD ports but might not be
in other grub2 versions floating around)

	http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=699002

> Tom
> 
 HTH, :)
	Juergen


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