diskboot.img Documentation problems

Jerry Williams jwilliam at xmission.com
Sun Jan 21 23:58:33 UTC 2007


> -----Original Message-----
> From: fedora-devel-list-bounces at redhat.com [mailto:fedora-devel-list-
> bounces at redhat.com] On Behalf Of Jerry Williams
> Sent: Sunday, January 21, 2007 12:16 AM
> To: Fedora Developent
> Subject: diskboot.img Documentation problems
> 
> Not sure if this is really the right group to post this to.
> 
> The docs need more work and maybe some packages need some changes as well.
> 
> http://fedora.redhat.com/docs/install-guide/fc6/en/sn-preparing-usb-
> media.ht
> ml
> 
> I would suggest changing anaconda-runtime
> /usr/lib/anaconda-runtime-mk-images.x86 to change the README that goes
> into
> /images/README to have a link to the installation guide.
> 
> The installation guide really isn't correct when it comes to using the
> diskboot.img file. Should almost include
> /usr/share/doc/syslinux-3.31/README.usbkey in the installation guide.
> 
> It might have worked fine for a floppy, but the usb device has a partition
> table and the image doesn't include the partition table, just a file
> system.
> 
> So to use the command dd if=diskboot.img of=/dev/sdd is not correct.

Turns out that this does work on newer machines. 
fdisk -l /dev/sdd looks really funny, but it works just fine.
Thanks for the fix that just happened to the kernel (new diskboot.img) my
machine will now boot and load the menu for the install.

So not sure what to say about USB flash drives, depends on your machine.
I have one that works one way and another machine another.
But in either case I can't load the rescue image, anaconda has a problem
with being loaded from NFS when booting with a USB flash drive.
 
> WARNING!!!  WARNING!!! Be very careful using these commands!
> You could erase your hard drive!
> You need to use dmesg to find out what the name of your usb device is.
> I am using /dev/sdd which might cause problems it that is not your usb
> device or is your normal hard drive device name.
> 
> The instructions I have seen look something like:
> dd if=/dev/zero of=/dev/sdd
> /usr/lib/syslinux/mkdiskimage -4 /dev/sdd 0 64 32
> which creates the /dev/sdd4 partition
> Then dd if=diskboot.img of=/dev/sdd4 works fine.
> Or
> /usr/lib/syslinux/mkdiskimage /dev/sdd 0 64 32
> dd if=diskboot.img of=/dev/sdd1
> 
> The problem that I see is that if you have a large usb device it can take
> a
> long time to write zeros over the whole thing and then format the whole
> thing just to turn around and write a small file system over it.
> 
> This is where the small 16MB flash card that came with your camera is a
> good
> thing to use in a usb adaptor. :)
> 
> If all that needs to happen is to wipe out the partition table on the
> drive
> then dd if=/dev/zero of=/dev/sdd count=1 works fine.
> You should look at /usr/share/doc/syslinux-3.31 to help figure out the
> numbers for mkdiskimage if you have a large usb flash drive.
> 
> /usr/lib/syslinux/mkdiskimage /dev/sdd 13 64 32 is much quicker and has
> enough room for diskboot.img image.  But may not work on all devices.
> I had problems with a 1GB device.
> 
> 
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