KPK2003, sorry, I didn't see your question until today. In summary (and to answer some of the questions from later posts), I used 3 USB flash drives, 2 x 16Gb and 1 x 8Gb. As some people have noted, the image for the first disk was >8Gb, so I put it on the 16Gb drive. I copied the pkgdb folder and the config.nfm. I turned on the cars to the accessory mode (single press) and inserted the first flash drive into the glovebox USB port; after 30-45s, the flash drive was recognized, and I initiated the update. Each USB took about 20 mins to copy over. Both cars, at some point, shut down by themselves, though the copy seemed to continue in the background. When I pressed the start button, the copy appeared to reinitialize, with the car asking for USB1; however, it wouldn't actually recopy files. Rather, it ask for, e.g., USB1 and the progress bar would jump to ~36%, then ask for USB2, etc.
I hope this helps.