To create an ISO on a Mac (without using Toast or similar), you can use the cdrecord and mkisofs tools from Linux. Install cdrtools using some method. 🙂 This should give you access to “mkisofs”. I cheated and located a copy of mkisofs inside of VisualHub and used that.
Suppose that you want to re-master a Centos linux bootable CD. You copy the contents of the isolinux directory to a convenient location on your Mac. Open a terminal window. Change into the isolinux directory and make whatever changes you need to make to the files located therein. Then do this:
mkisofs -o boot-ks.iso -b isolinux.bin -c boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -R -J -v -T .
This will generate a new file named boot-ks.iso in the current directory. That’s it.