Re: [Qemu-devel] [Bug 586175] Re: Windows XP/2003 doesn't boot

[Kevin O'Connor <kevin@koconnor.net>]

On Sun, Jul 25, 2010 at 08:15:24PM -0000, CurtisNelson wrote:
> My next step at this point was to install hexedit and compare the two
> resulting images.  Specifically, the mbr at the beginning of the disk
> and the ntfs partition starting at sector 63.  On the net there is some
> talk about changing 0x7E1A to 'FF' -- which is supposed to indicate disk
> geometry of the ntfs partition.  There were three values that were
> different at this point in the ntfs file region -- 0x8E18, 0x7E1A, and
> 0x7E1C.  The first two did not seem to have any effect.  But changing
> 0x7E1C to the value of '3F' would result in the image booting properly.
> Evidently this is the part of the NTFS file system that records the
> starting sector of the partition.  This change successfully booted all
> my test cases restores with a single partition.

This looks like some hd geometry confusion.  You could try playing
with the qemu "-hdachs" option to force a different geometry
translation.

You might also want to capture the seabios log to see what it thinks
the drive geometry is.  On qemu you can add the following to the
command-line to see the seabios log:

qemu -chardev stdio,id=seabios -device isa-debugcon,iobase=0x402,chardev=seabios

look for lines like:

"drive %p: PCHS=%u/%d/%d translation=%s LCHS=%d/%d/%d s=%d\n"

-Kevin