I am having pretty much the same problem because my drives are all vfat. when i mount something to a mountpoint its read only.I had another thread somewhere on how to mount my hard drives and partitions themselves and it works fine

i cant seem to get -o rw to work with loop?

So i guess my question is how do i mount my .iso with rwx permissions to my vfat drive? thanks.

I realize that this may be a necropost,but it is the first topic/link that pops up in google with the keywords "linux edit iso image"
Try:
sudo aptitude install isomaster

ISO9660 filesystems can only be mounted read only because the filesystem is read only by definition. Rockridge, Joliet, UDF, etc are in the same boat. You'll need to copy to a new dir structure and recreate the ISO. You'll probably lose the boot record in the process.

Dude, we're in the Fedora forum, not the forum for Debian or some derivation thereof
What you should have suggested is:

==How to Make your own .iso==

collect the files you want in a folder
burn them to a CD or DVD
use the following cammand in terminal as root:

dd if=/dev/sr0 of=xxxxxxx.iso

Waste of a CD, maybe you should have a look at this

this is what I'd do

mount and copy the iso contents to a folder as linuxnewbie said

then, after editing you have to recreate iso as best you can like original
and because it's Fedora you gotta "label" the iso too
it says in the isolinux.cfg what the label is

so, assuming iso is extracted to a folder named "ISOTMP"

mkisofs -r -V "LABEL" -cache-inodes -J -l \
-b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot \
-boot-load-size 4 -boot-info-table -o NAME-OF-ISO.iso ISOTMP/

thats if there is a isolinux folder in iso, instead of /boot/isolinux
?

What should you do if you still have this problem today?
To edit ISO image or file , you can follow this program :https://www.iseepassword.com/iso-editor.html