Downgrading Quantum From Unity to Concept

I have several Modicon Quantum 140CPU43412A controllers that I want to downgrade from Unity OS to Concept OS. I first swing at it was to use the ProworX ExecLoader but that failed. Any other possible means?
Thanks
Dan

When you say it failed... in what way? Error message?

Do you have the firmware CD image thats downloadable from the Schneider website? There's a good PDF in there that gives you the exact steps. Also the firmware images.

You need unity installation DVD and Unity OS loader of course because you have Unity CPU.

http://www2.schneider-electric.com/...l_NL/FA20583-Premium_Upgrade_Procedure-EN.pdf