Digging into a Red Hat bootnet.img image
Updated September 16, 2002
Created August 24, 2001

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Unpacking bootnet.img, initrd.img, and modules.cgz

#Insert the Red Hat CD-Rom disk 1.

mount /mnt/cdrom
mkdir /tmp/bootnet
cd /tmp/bootnet
cp /mnt/cdrom/images/bootnet.img .
mkdir bootnet.img.dir
mount bootnet.img bootnet.img.dir -o loop
cp bootnet.img.dir/initrd.img .
mv initrd.img initrd.gz
gunzip initrd.gz
mkdir initrd.img.dir
mount initrd initrd.img.dir -o loop
cp initrd.img.dir/modules/modules.cgz .
mv modules.cgz modules.cpio.gz
gunzip modules.cpio.gz
cat modules.cpio | cpio -idv

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Repacking an initrd

find 2.4.7-2BOOT/ | grep -v "BOOT/$" | cpio -o -H crc >modules.cpio
gzip -9 -n modules.cpio
mv modules.cpio.gz modules.cgz
mv modules.cgz initrd.img.dir/modules/modules.cgz
umount initrd.img.dir
gzip -9 -n initrd
mv initrd.gz initrd.img
mv initrd.img bootnet.img.dir/initrd.img
umount bootnet.img.dir

#You are now ready to use your modified bootnet.img floppy image.

• If your initrd is too big to fit back onto the floppy, you may delete the *.msg files on the floppy.
• If it still doesn't fit, then try deleting unneeded items from your initrd or modules.cgz.
• If you still can't get the new initrd.img to fit on the floppy, then grab a fresh initrd from a bootnet.img floppy, and then copy your contents into this fresh initrd. It seems that once you cause the initrd.img to expand, it doesn't automatically shrink the way we need.
• If you need to build a new kernel or modules, you will want to build the kernel with SMP disabled. You should also make sure that you put the correct string when building a new kernel or modules - you should take "-2BOOT/" from "2.4.7-2BOOT/" and put it in the Makefile as shown in ../kernel.html.
• If adding drivers into a modules.cgz, you may need to modify the other files in the modules directory which resides in bootnet.img.
• module-info - You may select from these entries during installation.
• modules.cgz - Contains the drivers files
• modules.dep - ??
• pcitable - Information from performing an "lspci" and an "lspci -n".
• When initrd boots, it immediately runs /linuxrc