I was having crazy problems - first nothing suddenly - a suddenly corrupted SD card seemed the answer and it did start almost working. Then, a new problem, it will follow 1V/oct cv sometimes, not others, where it will output a single note only. I had solved some similar issues with my Poly Cinematic by updating firmwear, so I did the same with Pianophonic, but now it wont respond to anything, no front panel lights at all.
Eric
The firmware update procedure is quite different on Pianophonic compared to Poly Cinematic. Check that you have done this correctly as you may have just installed a new boatloader and not completed the second stage where you boot up Pianophonic as a usb drive.
The v/oct issue is a limitation of Pianophonic itself where it can only transpose one octave up and one octave down, this includes the Pitch control so you may hit the limit early. The trick is to pick a root note over midi that is in the centre frequency of your tune, so a base line should start with a bass note.
Finally, we have new firmware coming out later this week that resolves the SD card issue, so worth waiting for that if you can.