Firefox – How to redirect YouTube’s videos URL (googlevideo.com) from HTTPS to https automatically

According to After updating to 14.0.1 Firefox will force https on websites. How do I fix?, this is due to auto-completion:

it is because of the autocomplete. Is there any way to fix this without disabling this feature though?

So far, I haven't read about any ways to change how the autofill URL is selected from history.

If you turn off urlbar.autofill, then Firefox 14 will behave like Firefox 13: (1) the drop-down of list of matches from your bookmarks and history will appear below the address bar, and (2) if you don't choose a match from the list but instead press Enter, Firefox will load http:// + what you typed (or if you typed separate words, it will run a search).

If you've previously visited the HTTPS version of the page, you will see this when typing "xkcd" into the address bar:

When hitting Enter at this stage, you will land on https://xkcd.com, just like you're experiencing.

You can also highlight the https://xkcd.com in the dropdown and hit Del. The URL will then be removed and will land on the HTTP version the next time.

I noticed using Fiddler that sending HTTP requests to Google would always return the 302s you mention, redirecting me to the HTTPS url as long as a Firefox user agent string was included in the request header. This is my current user agent string using Firefox 24 on Windows 7 x64:

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Firefox/24.0

So for me, a simple fix was to start using the User Agent Quick Switch add-on for Firefox. I changed my user agent string like this - just removed the Firefox/24.0 at the end:

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101

I'd guess a similar change to your Ubuntu user agent string would also do the trick, although there is an outside chance that it be problematic on another site.