In 31.8.0+ and 33+ releases of Firefox, Mozilla has dropped support for less secure (weaker) certificates (Error code: ssl_error_weak_server_cert_key). While this extra security is nice and all, the behaviour cannot be currently customized to be able to access older devices that cannot be upgraded to use better certificates. Hence, keep an older version of Firefox around for such cases. Reference bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1180526
The 'convert' tool is needed during the build.