Editing a Bootable PC ISO Image using OSX

If you want to edit a bootable PC ISO image or CD on OSX here is how to do it.

Disk Utility can only mount ISO images as read only.
It can also make an image of an ISO cd and can also burn an ISO image.
Using hdiutil to edit PC bootable ISO images leaves the image non bootable.
mkisofs can make a bootable PC ISO image from a folder on OSX but it needs to be installed first.

These instructions are for editing a bootable PC ISO file using OSX and keeping it PC bootable with a PPC version of mkisofs.
Maybe the PPC version of mkisofs will work on Intel macs but you might have to find an Intel Mac version (see http://wiki.onmac.net/index.php/HOWTO).

From http://homepage.mac.com/machiavel/Text/AquaCDBurn.html
download cdrtools (cdrtools-OSXbin.tgz).

Look around in the unarchived cdrtools folder and find the sw folder and then place the sw folder in the Applications folder.

Start up the Terminal and then in the Terminal enter

sudo cp /Applications/sw/bin/* /usr/bin

This installs mkisofs and the sw folder can now be trashed.

Create a folder (I'm naming the new folder newcd) and then mount the original PC ISO file and copy it's files over to the newcd folder and then place the newcd folder in the Applications folder.

You can then edit the files in the newcd folder or add or delete files and the changes will be on the new bootable ISO image.

Then in the Terminal enter

cd /Applications/newcd

Then in the Terminal enter

mkisofs -b boot.img -no-emul-boot -boot-load-seg 1984 -boot-load-size 4 -iso-level 2 -J -joliet-long -l -D -relaxed-filenames -N -V CDOut -v -x .DS_Store -o CDOut.iso .

The boot image file needed for booting on a PC is boot.img in the above example (which should be in the newcd folder).

You should change this name to what the boot image file is called in your newcd folder.

In the above example the finished ISO image file is called CDOut.iso and it's volume name when mounted is CDOut.

Instructions on making an XP ISO boot disk using OSX are at