Did you mean to explicitly add the tx buffer back on the client?  An earlier commit moved the tx buffer from being on each client instance to being local to the fastrprint function (only thing that uses the tx buffer): https://github.com/adafruit/Adafruit_CC3000_Library/commit/4cf420010e0d8f5331958e846c608e32d3d173da  It looks like the rest of the changes in the tx buffer removal commit are in this pull request, so this was probably just something small missed merging in changes.