The FreeDOS image is 1.44MB so if it's mounted to the /tmp/cdr directory, then that's the amount of space you have to work with on /tmp/cdr. You can try a larger image size as listed under 'size contraints' on the first page or another method (also listed there). Here's a direct link to the 2.88MB image:
Originally Posted by wayward4now
To be clear, the files you are trying to copy over exceed 1.44MB, which is the amount of space you are working with, not the size of a 650+ MB CD (that's just the max size/medium you are using to store it). Remember, with this method, you are constrained to the size of the FreeDOS image so your files must come in under this limit (or 2.88 MB provided above) or you must use another method like using GRUB. Your other option would be to use flashrom.