[lkml]   [2002]   [Dec]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: Unable to boot a raw kernel image :??
    DervishD wrote:
    > Hi all :))
    > A time ago I was able to generate bootable Linux CD's just by
    > dd'ing a floppy containing a raw kernel image:
    > dd if=/dev/fd0 of=eltorito
    > After that, mkisofsing, toasting and booting. But now, depending
    > on the machine, I have 'invalid compressed format' errors, or even
    > ye olde register dump when the image was damaged :(
    > Booting directly from the floppy works, but booting with that
    > same image from a CD does not :(( I now I can use LILO, or better
    > yet, Syslinux or isolinux, but I'm just curious why I cannot boot raw
    > image-based CD's anymore.
    > Anyone knows what's happenning here?

    I had this problem a while ago. It turned out to be a (widespread)
    BIOS bug triggered be the disk-size probe of the kernel's boot loader.

    The crude fix which worked for me: disable the probing for 2.88MB disks
    by changing the first byte of the disksizes table at the end of bootsect.S
    from 36 to 18.

    The long explanation: The BIOS allows bigger-than-track-size reads
    in El-Torito mode which confuses the probe routine which then assumes
    a 2.88MB disk when the BIOS is actually emulating a 1.44MB disk.
    In LBA mode that would be no problem but in CHS mode (which is used
    by the loader) it does not work.

    Ciao, ET.
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:31    [W:0.067 / U:108.604 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site