We've been using the FX150s for a couple of years as personal monitors in our band and they are great. They've survived a lot of abuse and I recently discovered the firmware update was available for them. We have 6 of these by the way! One of them, will not allow me to factory reset it - no matter how many times I've tried, I simply cannot access the input trim on channel 1 or 2. Another bizarre issue is that the vocal tone button is pale green when nothing is connected and when I press it down, it turns pale red. Not flashing, steady. Only unit to do this! It allowed the firmware to be updated like the other units, but they allow the input trim to be altered (as per the instructions in the manual). Not sure if this is a fault with the unit, something we can easily overcome or if there's a manual firmware fix for this out there? Anyone seen this before? Any suggestions would be gratefully received. Many thanks!