This is a PB plus 2.1 auto level bracket and wrench. You will need
#6 - 32 x 3/4in round head machine bolts and #6 washers. this replaces the two bolts on the right side of the extruder carriage.

This is the modified firmware to work with the PB2.1. Because the bracket can't be mounted in the same place as the Simple, I need to change the values where the probe levels.

https://www.dropbox.com/s/39pcwe1z0twwp4f/PB21BetaFirm.zip

This firmware seems to be working well over here. When homing your xyz. Click the individual icons, home all seems to have a bug (ONLY IN MANUAL CONTROL, PRINTING WILL HOME FINE)

If you find any bugs contract me on twitter @matthewphone