How did you previously set up your Firefox bookmarks on Android -- did you synchronize them with your desktop Firefox using the Sync service? If so, you should be able to set up Sync again. See whether this article is helpful: [[How do I add a device to Firefox Sync?]] If the bookmarks were only stored locally on your mobile device, I'm not sure whether there is a copy of them anywhere. Were you using any backup software or add-ons?