I wanted to share my experience with making the Motor Bridge Cape work with Debian 8 Jessie on the BBG. I think it was only tested with Debian 7 Wheezy. I used this image debian.beagleboard.org/images/b … 4gb.img.xz, with the 4.1.23-bone-rt-r21 kernel.
The I2C bus mappings between the 2 OSes are different. What was I2C1 on Wheezy is now I2C2 on Jessie. I think this is actually an improvement, as the mapping did not match the AM335x I2C module numbers on Wheezy. An explanation can be found here: datko.net/2013/11/03/bbb_i2c/.
To make the Motor Bridge Cape work on Jessie with the Seeed python libraries, I needed to change line 37 of MotorBridgeCapeforBBG_BBB / BBG_MotorBridgeCape / MotorBridge.py to:
MotorBridge = Adafruit_I2C(0x4b,2)
I might suggest that the code detect the environment, or at least allow the user to set it. Jessie seems like a much superior OS in my limited testing.