Sorry to revive an old post, but I've recently been dealing with this. And I wanted to share what worked for me. I bought another used POD HD desktop from ebay. I couldn't update the Flash memory, POD HD Edit couldn't connect and my DAW couldn't see it.
Specs:
POD HD desktop
WIN 7 (and WIN 10) machine
I kept getting that 8000...* error. I tried different USB ports on my PCs. I tried different USB cables. Nothing. I tried to do a factory reset (power it on while holding left on the navigation pad). It would reset either. I'm thinking this POS is bricked.
A little more persistence paid off. I plugged in the USB cable, and then I was able to do a factory reset (left nav pad and power on). Then I fired up Line 6 Monkey and I could update the flash memory (I downloaded the update from the Line 6 software page) via where I downloaded the file to. Now everything works as expected. What a PITA! LOL.
Good luck to others.