I’ve been reading various forum posts and trying various options as this worked without any problem on our Fire TV Stick.
I’ve switched HDMI cables, tried a different HDMI port on the television and that didn’t make a difference.
I restarted the Fire TV and then there was an update available. Installed the update but that didn’t seem to make a difference either.
Until now I was focused on Bosch as that was the show I was watching on the Stick and on my phone.
I looked at the list of other described programming available on Amazon. I looked more for the shows or movies that are free with Prime as I wasn’t ready to spend any money yet, trying to get this working.
After having Alexa find the title I was looking at online, I noticed none of these had Ultra HD next to them on the Fire TV as Bosch did.
I played these movies, no problem at all selecting English Described in the menu during playback. I tried about four and all worked fine as they are supposed to. Just for kicks I decided to give Bosch another try.
I had Alexa find Bosch and this time the Ultra HD was missing on the Fire TV.
I played an episode and now the English Described was there in the menus as it was supposed to be and as it was in the other movies and shows I just had success with.
I’ve gone back into the regular menus and then back to watching Bosch and the Ultra HD was still gone and I can still access the setting for English Described during playback.
This seems to be some sort of a bug I encountered in Fire TV. I’m not sure what got me out of the bug, restarting & updating, restarting a few more times or maybe watching the other content that wasn’t marked as Ultra HD.
One thing I know for sure, the person my Wife spoke with at Amazon Disability Support was 100% wrong that we need a 4K television to get the English Described audio setting with the Fire TV.
Also unless you know that your tv / AV receiver etc.. setup supports Dolby Digital Plus, its best to turn that off in the Display & Audio settings of the Fire Tv.
Another tip I recently learned of, if your TV isn’t a 4K tv, one way of preventing this issue or bug I’ve been messing with is to change the display resolution in the Fire TV from auto to 1080P. That can be found in settings, display & sound.