This is not a firmware-related issue. Instead, you'll need to adjust your sensitivity and threshold settings, as well as your crosstalk settings (if the hits are being missed while striking another pad consecutively).
To adjust these settings:
Hit the pad whose settings you want to adjust, or press its corresponding Pad Select button.
Press Utility, then press Page/Select until the desired setting appears in the display.
Sensitivity will control how responsive a pad is when you hit it. The higher the value, the less forcefully you need to play to generate a loud hit.
Threshold controls how forcefully you have to hit the pad to generate a sound. The higher the value, the harder you have to hit it.
Crosstalk is the unintentional triggering of a pad when an adjacent pad is hit. The higher the value, the less likely the pad will be triggered by crosstalk.
I hope this helps! Let me know if you have any additional questions.