I normally run x86, so I had to mark firefox and some other deps as ~x86. After emerge -u mozilla-firefox I got: Updating firefox chrome registry... /usr/libexec/mozilla-launcher: line 648: regchrome: command not found E: regchrome exited with status: 127 E: //usr/lib/mozilla-firefox/extensions/installed-extensions.txt still present E: Registration might have gone wrong www-client/mozilla-launcher-1.42 is currently installed. Maybe a newer version is required?
*** This bug has been marked as a duplicate of 114041 ***