I don't know how to push "desktop" bookmarks from mobile to desktop. Maybe someone else knows a trick for that. But meanwhile, did you check for possible automatic backups of your bookmarks? The following article has the steps: [[Restore bookmarks from backup or move them to another computer]]. If you aren't seeing any bookmark backups on the Restore menu, did your Firefox create a new profile? In that case, it normally starts up like a new installation. You could check the first section of the following article (about using the About Profiles page) in that case: [[Recover lost or missing Bookmarks]].