Hi

I recommend having a read of this article that will help you to install Firefox on a Kindle Fire device.

I hope this helps, but if not, please come back here and we will do our best to assist.

I have a Kindle Fire 8HD and there is not option in settings to select "Apps from Unknown Source." What next?

Do the steps in this Amazon help article work on your device: https://www.amazon.com/gp/help/customer/display.html?nodeId=201482620

Reading that article a little more closely, it looks like the location changed. It used to be under Settings > Applications and now it's under Settings > Security. If you can confirm that, we should have someone update the help article here.

Confirmed - you are correct. Thank you.

Why has Amazon App store stopped offering Firefox?

The page for current Android Firefox Release is at https://www.mozilla.org/firefox/android/all/

allanhorne said

Why has Amazon App store stopped offering Firefox?

Mozilla wanted to put the Android Firefox on the Amazon appstore as Mozilla did have Android Firefox 9.0 up there briefly years ago. However it was found that Amazon modified and resigned the apk which caused update problems so Mozilla pulled it shortly after. Mozilla has contacted Amazon many times about modifying this policy, so far Amazon has been unwilling with no progress from them since.