I just got Bittle setup. Most commands are working flawlessly, however Bittle's walking is very unstable. I've gone through calibration several times with the 90 degree measure on flat surface.
I downloaded a the latest zip from GitHub. I've included the libraries, uploaded WriteInstinct and OpenCat.
Here's a video of his current walking:
Remove the rubber toe will solve the problem. It increases the friction for special cases, but not helpful for walking with current parameters.