iDerect 3100 iNFINITY problem, keeps restarting.

1. Start be confirming that your opt matches the image on the iDirect.  
2. Ensure that the opt is NOT a hub side opt.
3. Stop falcon (from console) and navigate to /etc idirect/falcon directory and CAT the new options file in.  

service idirect_falcon stop

From console:

cd .. (moves you up one directory to the parent dir)  You are probably skipping this step, which is more than likely your problem.
cd /etc/idirect/falcon/
pwd (confirms your present working directory)
ls -l (you will see falcon.opt in the contents)
copy the good opt in notepad
cat > falcon.opt (enter)
right click - paste to host
Enter once (at the end of the paste)
Control-D (done)
type reboot

Do not forget to move up one directory to the parent before you navigate to etc/idirect/falcon

It is very important to always confirm your present working directory with the pwd command so you know you are CATing into the right place.  It is equally important to ensure that you move up one directory (cd ..) to the parent prior to navigating to the etc/idirect/falcon directory. 

Happy to hear you have it working.