Well the only "factory reset" option I could see changed settings back to their defaults, but it didn't restore the firmware to some earlier state.
Right, firmware is firmware and it doesn't usually have any roll-back feature in consumer devices like this. If you want a different version, you have to flash it, and it's usually a good idea to save a "just in case" copy of whatever version you're writing over, if the utility will allow it.
What a factory reset does, or should do, is completely reset the unit's configuration (and user-modifiable storage spaces that hold these settings) to an untouched state. Sometimes that gets rid of a troublemaker, especially if the unit has attempted to preserve user-modified settings across a firmware update.