[GeoffR]

Some people have reported simlar problems after other firmware updates too, I think it is often that something has gone wrong in the update process rather than the firmware version itself being slow.

So if this is the only reason for going back to an earlier firmware version, before doing a factory reset you might try just powering off/on, and if that has no effect try logging out of your account, which will rebuild the database and might fix the issue. If all that fails then a factory reset is still an option.