mus1prod

If different usb port/different machine doesn't work, and factory restore or flash update doesn't work, try this:
 
Just do a midi dump from the pedal board itself. You don't need any midi software open on your computer, just make sure your computer is on and the pod hd300 is turned on and plugged into a usb port on your computer. Follow the instructions, that are in the manual, on how to do a midi dump -"ALL". You may need to power-cycle the pod and reboot your computer afterwards, but I've found that this does the trick every time.
 
Why this works: Honestly, since I don't work for Line 6, or have the schematics or any design information on the product I can't be 100% sure. My best guess would be that since the pods connect to, and exchange data with, the computer via midi-over-usb, there is a voltage-high(or low) situation with the eeprom. Kind of like when old analog telephones would act like they were busy when they weren't. There is the "on-hook" voltage(3v I think) that drops when you pick up the receiver. That change in voltage is the signal to the phone company's switch that signals that the phone is in use. When you hang up the phone, the voltage goes back up. If the voltage gets stuck low, then it looks like the phone is always busy. The only way to fix that was to disconnect the exterior test jack or incoming lines, temporarily, to reset the voltage. Doing a midi dump on the pod hd300 acts much the same as disconnecting and reconnecting the exterior phone lines.
 
Give it a try. If this works for you, let Line 6 know. And if you're the Line 6 moderator reading this, and it works as a consistent solution, let your bosses know. I could use a change in jobs.  ;-)