Changing the homepage is currently not possible in Firefox for android. Hopefully this feature will come to Android devices soon, but for now there is no ETA.

I could have swore i saw that firefox 20 for android would have that feature.

Are you sure you got the latest version of Mozilla Firefox for your android device? I'm pretty sure it's not possible to change the homepage yet, but I might have missed something. I'm using iOS myself.

Hi Rydafromtha253 and cityofulysses:

As of Firefox 20, it is possible to do some Firefox start screen (home page) customization (we just documented it so it's easy to have missed it).

You can: pin a site, remove a site by unpinning it and edit a pinned site's url.

Please read the following Knowledge Base Article for complete information and directions:

Pin Sites on the Firefox for Android start screen

Hope that helps!