MBRGuru - The dealer had 2 of the update flash drives and we tried both with the same failed result. I did find out the part number of the "extension box" that is supposedly required to fix it, and I looked it up on-line. I did not find out much except that it is about $1,000, which seems awfully expensive. The part is due in tomorrow and hopefully I will be back in full operation again.
That's part of the system, so looks like they're just going to get you a new one probably per-configured with the new software.
Failure to complete an update can... and apparently did... kill the device. It's interesting how people take updates for granted now. That's great confirmation of progress; however, the exposure of a flash bricking hardware still exists... though much less likely than in the days of yesteryear. This is why only a small number of owners are get the wireless method. USB has exposures, but fewer than transmission over a local home network, via a bluetooth phone connection.
I just went to the Gen III Audio subforum as Tracksyde noted, and a fair number of people there report the same problem and symptoms. Toyota initially seemed to be telling them it was the flash drive but most of the successful resolutions now involve replacing the Entune extension box. That is supposedly what the dealer should have for me tomorrow. Hope that resolves my issue but I have to say that I am totally unimpressed by Toyota's apparent lack of pre-testing before rolling out an update, and their support's general lack of knowledge about even the fact that there was an update much less a potential problem with it. I would also think that it should be possible to have a backup plan, for example being able to restore the last working software version. I'm and engineer and still really like my seagrass pearl marvel. I drove 2 people and luggage up to Tahoe and back 2 weeks ago averaging 58 mpg - using mostly gas because of the distance. The hotel even let me plug in at night in the garage so a fair amount of local travel there was at no gas cost.
Hooray! I just came back from the dealer where they replaced the Entune "extension box" and the update now worked without hanging in step 6. It took a few days longer than expected because they have few technicians that are familiar with it. The dealer did initially disconnect the accessory battery initially attempting to reset the Entune update and I notice a few things that I have to re-enter such as the dash time and date, but hopefully everything is fine.