Date: Fri, 23 Aug 2013 21:25:50 +0000 From: nox@FreeBSD.ORG (Juergen Lock) To: Thomas Mueller <mueller6724@bellsouth.net> Cc: "Andrey V. Elsukov" <ae@FreeBSD.org>, freebsd-stable@freebsd.org, Juergen Lock <nox@FreeBSD.ORG> Subject: Re: Change in loader or kernel: won't boot with kfreebsd in grub2 Message-ID: <20130823212550.GA95148@hub.freebsd.org> In-Reply-To: <FA.55.18705.24A75125@hrndva-omtalb.mail.rr.com> References: <FA.55.18705.24A75125@hrndva-omtalb.mail.rr.com>
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On Thu, Aug 22, 2013 at 02:41:06AM +0000, Thomas Mueller wrote: > > 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 > > I tried to boot the FreeBSD partition directly from Super Grub2 Disk with chainloader +1, but was not successful. > Well that just run loader which seems to have issues on your box as you said. (or does on mbr at least) > I think some FreeBSD boot code is in a small boot partition such as I have on the USB-stick installations, installed with gpart. > ...so if this is gpt you may need to chainload that partition in fact, yes. > I wonder if "linux16 memdisk" from grub2 is the same as "KERNEL memdisk" in syslinux: was planning to try it on FreeDOS 1.1 installation fd11src.iso . > They both boot memdisk so kind of similar, yes. > I also have a memdisk in the latest syslinux installed from FreeBSD ports. > > Once FreeBSD boots from the USB stick, it accesses the GPT partitions OK as far as I can tell. > Ok so only loader has difficulties... As I said try the latest super grub disk iso, that might still be able to see the partition and if yes boot the kernel directly from there w/o loader. > I could even check with a USB-stick installation of NetBSD, though NetBSD is much less stable than FreeBSD on my modern hardware. > > I was even thinking of making a giant floppy image, not to write to an actual disk, but to boot via grub2 or possibly grub4dos. > If you already use grub2 then it only needs the mentioned patch (and be able to see your FreeBSD partition), then it should be able to boot the kernel directly w/o loader as I said. > I would copy /boot but not including the modules to another directory, apply makefs, mdconfig, mount this image, and bsdlabel. > > I did something like that with NetBSD 5.1_STABLE i386, and it worked with grub4dos. > > I would of course have to interrupt the boot to be able to specify the root file system, as I did with NetBSD, or maybe put into loader.conf . > > map --mem --heads=16 --sectors-per-track=63 (hd0,2)/boot2/nbffs51c.img (fd0) > map --hook > rootnoverify (fd0) > chainloader (fd0)+1 > boot > > and hit the spacebar in time to get the boot menu, so I coulld type > boot netbsd -a > to specify the root file system, or I could boot any other kernel present in the 40 MB "floppy" image. > > Grub4dos, being born from DOS, requires setting a (fictitious here) disk geometry. > ..so all that sounds superfluous. > Tom > HTH, :) Juergen
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