BrickPi not working after raspbian upgrade


I have one of the original BrickPi boards connected to a Raspberry PI A running Wheezy and connected to two Lego nxt motors.

Everything was working OK, however I decided to upgrade the Raspberry Pi to run Jessie by formatting the SD card and putting on the latest Jessie image and then reinstalling BrickPi. Since the upgrade my BrickPi has stopped working. The software I have written still runs without any errors but the motors do not operate.

I then reverted back to Wheezy and again reinstalled BrickPi, but again my code runs but the motors do not operate.

Any ideas what is going wrong?