That won't be necessary, the two firmwares are very close to one another. Asl ong you did one when you first switched to pixie dust.
Upgraded over the "pixie dust" version. Working good but less 5GHz range than "pixie dust". That one worked soooo much better as far as 5GHz range. the 33b3 is giving me more 2.4GHz range though than pixie dust.