I am running 3.14 on my Main Controller. Not happy with random yaw twitching . Having difficulty locating 3.12 version firmware . I am aware of the age of my unit. Just really hoping that firmware version 3.12 is still available . Any help would be appreciated . Thanx

Michael,
I looked here and did not see it, http://www.dji.com/product/phantom-2-vision-plus/info#downloads and not sure if I still have it as I cannot recall the form it came in, also, not sure if you can go backwards without a complete/hard reset but if I do have it I will Dropbox it sometime soon,
Good luck,
FYI...I am still on 3.12 and 1.0.48 vision app...no issues as after previous DJI firmware debacles I did not want to risk a working bird.

Bad news:  Essentially, there is no way to downgrade by simply reinstalling v3.12 -- if you will recall, for the Phantom 2 series the main controller firmware was downloaded through the Vision Assistant via an internet connection.  It was never released as a separate zip file that you could install on the SD card.

Having said that, there may be some good news:   (and boy, this one made my brain cramp up trying to remember where I read about downgrading from an update!) back in early 2015 there was a firmware update that was causing a lot of ERROR [25] -- IMU initialization failures which resulted in bricking a lot of Phantoms.  Needless to say, people were scrambling to find a solution.  I eventually found something in my notes that purported to have a solution that included downgrading the firmware.

Having said that, I ain't making any promises!  You do this at your own risk, electrons may be harmed in this process, adult supervision recommended and throw in any other disclaimers that may be applicable.  Here is the thread:  For ALL users who were bricked by 3.10 (READ HERE)
(Let us know the outcome -- good, bad or indifferent)

The "random yaw twitching" has nothing to do with the firmware.
I have been flying with 3.14 for 15 months with no problems.
I would check and calibrate your transmitter before doing anything else, and use the assistant to check the smooth movement of the sticks.

john,
good point on the RC calibration, i overlooked it as the OP seemed intent the issue was 3.14 related.

OP, you may want to try this procedure as well

Thanx guys. Took johnwarr's advice . Focused on my endpoint calibration . Found issue with Slow Pan Yaw Mod Switch. Decided to go back with factory configuration . Will miss the slow yaw option . The amount of slow yaw use compared to the frequency of the yaw twitch did not justify the option. Good to hear from you guys again and Thanx a Million for the advice .

Michael Starley Posted at 2016-7-30 01:31
Thanx guys. Took johnwarr's advice . Focused on my endpoint calibration . Found issue with Slow Pan  ...

Glad you got it sorted out.