One might also try changing the size of the actual .iso file to match either a 2048-byte or a 2325-byte sector boundary.
I would do this as follows (assuming the .iso is 2048 bytes/sector, if not, you'd have to try the following with 2352 instead):
Divide the .iso's byte size by 2048. Chop the stuff after the decimal point (of your result value) off. Multiply the remaining integer value by 2048, and you'll know how many bytes to chop off the end of the .iso, or rather, how many bytes the .iso itself should actually be.
To actually do this, a file splitting/splicing tool should do the trick. Just enter the new byte size (that you calculated) as the size to split to, and give the first split file the .iso extension. (The second split file will be junk, a partial sector.)
Now try opening the new .iso. If it's not recognized and/or no filesystem shows up, then redo the whole process with 2352 bytes/sector.
Once your new .iso IS recognized, you'd have to extract all the files from it to a test folder to make sure the iso is actually complete (i.e. wasn't incomplete to begin with)...