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Stitching together a broken MSDOS image file

From: Radio Tron
Subject: Stitching together a broken MSDOS image file
Date: Sun, 2 Nov 2008 07:47:12 -0800 (PST)

Hello, I'm trying to repackage a broken bootable ISO, MSDOS, FAT16, Hard Disk 
Emulation, boot image, generated by Symantec Ghost 2.55. I don't know why it 
fails, but I know that the MBR boot loader is failing.. I use GNU GRUB 0.97 on 
my PC, and have read the "Hacking GRUB" section, but the "structure of Master 
Boot Record" and "format of partition tables" sections are incomplete. Could 
someone here help me by pointing me to some useful docs.. I'm trying to use 
common Linux tools to finish this project..

1. I first extracted the images FAT16 FS via dd from sector=63 onwards, and 
mounted that. Added stage2 and menu.lst to /boot/grub. Also added it to /boot 
and / (just to be sure).
2. dd to dump stage1, 429 bytes to sector 0
3. fat_stage1_5 to sector 1
4. Then mkisofs, and when i boot I get: GRUB GRUB GRUB, in an endless stream! 
Which probably means stage2 is not loading - but what am I doing wrong???

Also tried, stage1 stage2 at sectors 0,1. That works and I get the GRUB prompt, 
but NULL (<TAB> lists fd0, fd1.. fd6, hd0 which means stage2 clobbered 
something and broke HD-emulation??

I also get this error every time I run: mkisofs -b osboot.img -hard-disk-boot 
-o osboot.iso ./ (on the unpatched original symantec image - when i try to 
recreate the ISO)
Gives me: "Size of boot image is 48132 sectors -> Emulating a hard disk 
Warning: image size does not match geometry (48195)"

Should I increase the size of the partition by 63 sectors? I tried dd 
if=/dev/zero count=63>>osboot.img but that didn't work because fdisk osboot.img 
continues to reports 24066 blocks instead of 24098. I deleted the partition in 
fdisk but couldn't recreate it with 24098 blocks.

Where can i find docs that explain what I'm doing wrong..


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