Ok this is my first question for some help if possible
I own two phantom 2 quads the problem i am having is
they both seem to have a problem hovering stable and also i hear the motors
sort of speed up the slow down a little and they don't seem to fly stable they sort of glitch in hover
I may be wrong but could it be the latest firmware that was installed on the phantom 2 a while back
as they had not been used since then.
also does any members on here have any earlier versions of the firmware i could have
to try if it resolves the problem.

What kind of areas are you flying? Have you had either an IMU calibration of a compass calibration lately? When you have the unit idle, do you see whether the motors aren't spinning at the same speed? Have you checked the props? Do you happen to have a video of how it's behaving?

yes  fitted brand new dji phantom 2 props
done an imu calibration and a remote controller calibration also a compass calibration
flying in open space, the props spin all the same speed on idle

could it be the gains etc to high it is set as default
i have looked on you tube and other phantom 2 owners were having the same problem
but no answers to what caused it

tried them both again today
same problems . One 1 of them the motors or motor as it's hard to tell speeds or revs up sort of hunting
and does not hold in hover very well when this happens
the other P2 again i hear the motors increase in speed and causes the quad to give a bad twitching effect
as it twitches the quad flies to the left then the motors stabilize the quad then hovers for a little while then
it twitches badly again and then goes to the left again
any help  would be grateful   

i have checked the motors are the upgraded 2312 motors
the esc x 4 are version 2.1
i wonder if i am doing the upgrade with the wrong dji assist software
what version should i be using?
i tried flying with the old type phantom 2 props then tried the 9450 props
strange thing is when i leave the P2 running with props on in idle or slightly speeded up on the workbench the motors
behave fine on both phantom 2s the problem only happens in hover in the air

similar problem, for a moment it even seemed that it would fly away,  I used the csc and it fell from the sky into the snow. Today i wasnt able to come down , the stick didnt show any reaction.....I have the impression it is a highly dangerous under developped flying robot with an own will

Update everything and recheck all settings, changing them as necessary. Recheck the props, motors, ESC’s, cables, IMU...

Put the gains at default (click the Default button) and test. If they are the same, investigate what gains are and how to configure DJI gains. Then test different gains to see if it gets better.