If Windows calibration doesn’t stick, use:

She soldered the certificate into the back of the U706's case and set it next to the sticker that simply read UPD. The driver continued to blink and to learn, taking its updates not from authority but from touch, from error, from the crowded, messy, incandescent life of people who must steer through storms.

Some users found that "unofficial" or generic versions of the U-706 (like those branded Quantum) have higher failure rates and weaker vibration motors. Are you experiencing a specific error (like the controller not vibrating) or looking for a download link for a particular operating system?