That is not currently possible.

Hi gmaster4u2 I’m replying to you because you posted a question about setting a homepage in the last few months. We’re testing a homepage feature in Firefox Nightly and we’d love to get your feedback before we release it to the public! Here are a few questions we have for you, but please include any other feedback: #Briefly describe what you expected the homepage in Firefox to be like. #How does the homepage in Firefox compare to your expectations? #Is anything missing from the ‘homepage in Firefox’ experience? #Was it easy or difficult to set your homepage in Firefox? #What is one thing you would change about the homepage in Firefox? Ready to give it a try? Here’s how it works: #First, allow third-party app installation on your Android. Go to your Android Settings and enable 'unknown sources' (usually under "Security"). #Download and install Firefox for Android Nightly at nightly.mozilla.org # Open Firefox for Android Nightly, then in the menu, tap Settings -> Customize -> Home -> Set a Homepage # Enter a homepage by either typing in a URL, or put a check mark next to ‘Use current tab’. # Finally tap ‘OK’ to set your homepage. You’ll will see your homepage every time you restart Firefox for Android Nightly. Cheers! ...Roland