Ran into my first glitch today on the new firmware. I am using the mp6 to transfer old minidiscs to my mac using usb C (no 3.5mm audio input on the mac). Took a minute to configure the 1 & 2 inputs to USB outs and that is working just fine. While doing the first transfer I figured I should save the settings to a preset on the SD card. I navigated to the preset menu, named it, and when I hit 'ok' to save, the mp6 went into this loud feedback loop that required me to turn off the unit to remedy. I reloaded the preset when power was back on and everything is working perfectly.
Worth noting, I am not recording to the mp6, just using it as a passthrough device. The only thing the device is doing is monitoring levels.
*I think what I did was save a preset with the same name and it did not like that. Forgot I had already saved one.