[syslinux] Memdisk/floppy image question

[H. Peter Anvin]

ganapathy murali krishnan wrote:
> I need to create a DOS image larger than the usual 2.88MB. I can't use a
> hard disk image (since I want the real hard disk to be called C:). I am
> trying to use a 9MB floppy image. My question is related to the process
> of creating such an image. Here is what I did.
> 
> * Create a file of size 9MB.
> * Use losetup, format it using FAT filesystem.
> * Copy all the files I want (IO.SYS,....)

So far so good...

> * dd the first 512 bytes from a 2.88MB floppy image to the new file.
> * Compress the file.

Nope.

Can't do it like that.  The first 512 bytes contains the DOS superblock
as well as the bootstrap code; you must not modify bytes 11-61
(inclusive, 51 bytes total) in the formatted image.  You can do this
with dd.

	-hpa