The SDXC update is a separate update from the firmware one, BUT, when you update to get the SDXC update you also update to the most new firmware, meaning, taht if you where on 2.0 on the moment on which that was the newer firmware, put the sdxc and get the update, you whould get the update on 2.0, but if you get it now, it will update your firmware to the lastest.
That said, there is a way to obtain the SDXC update whitout updating your firmware, there are 2 tutorials:
here and
here
Everything said, if you format your sd to FAT32, you can use your sd card whitout the SDXC update, but if you want to use exFAT, update all or follow one of the two tutorials
Remember: SDXC update is separed from firmware update...