Notes on turning tomsrtbt El Torito into a Etherboot image: 0. Tomsrtbt (http://www.toms.net/) is an all-purpose rescue and utility 1-floppy Linux system. You can read all about it at the web site. These notes explain how to turn the El Torito version of it into a netbootable image for Etherboot. Note that the .img file is not an ISO image, it is a 2.88M floppy emulation image for writing onto a CD-R(W) with mkisofs. It's actually a minix filesystem. Inside it are the kernel bz2bzImage and initrd.bz2. 1. First uncompress the .img: bunzip2 tomsrtbt-2.0.103.ElTorito.288.img.bz2 2. Mount the image using loopback. You probably need to be root to do this: mount -o ro,loop tomsrtbt-2.0.103.ElTorito.288.img /media/floppy I've specified /media/floppy which is the floppy mount point for my system, but any convenient directory will do. 3. Copy the kernel image and initrd off it: cp -p /media/floppy/bz2bzImage /media/floppy/initrd.bz2 . 4. Use mkelf-linux (or mknbi-linux) to make a netbootable image: mkelf-linux --append='root=100' bz2bzImage initrd.bz2 > tomsrtbt.nb root=100 means use /dev/ram0 (device 1,0) as the root device. 5. That's it. Clean up by unmounting the .img: umount /media/cdrom tomsrtbt.nb can now be loaded with Etherboot. Have fun.