Hello,
I need some help regarding spinning of motors of my 250 quad
The top right motor spins first
The bottom right motor spins second
The bottom left motor spins third and
Finally the 4th spins
My connections are the following to my kk 5.5 blackboard
Top left motor >> M1
Bottom left motor >> M4
Bottom right motor >>M3
Top right motor >>M2
Note
The connections are taken with the board facing the front
Top left motor>>CW
Top right motor >> CCW
Bottom left motor >>CCW
Bottom right motor >> CW

The board is flashed with x copter firmware 2.9 by minsoo kin
The motors are not spinning at the same speeds which causes the quad to back flip(broke a prop in this process)
PLEASE EXPERTS HELP ME OUT WITH THIS

Which esc? Have you performed the esc calibration?

12a emax Simon Series esc
Yes I have calibrated them

ESC Calibration is required

first individually
then together via KK 5.5

I have done it separately one by one but how to do it.using the fc?

I am not sure how to do it through the FC. Not very versed with KK5.5   Maybe others can help.

But surely this looks more like sync issue (calibration).

I am sure there is no fault in the fc as it compensates for the tilts and turn that I make by holding it in my hand..
I have throttle calibrated the escs but still no sign of it flying smoothly without flipping

May be FC to ESC connections or motor directions changed.

Post pictures of ur quad also pic showing ur connection and a video of the prb without props will be good

No akhilzid sir everything is right and I have cross checked it almost ten times

I tried it again and now the left motors are starting first just followed by the right ones
The left part lifted but the right one didn't that's cause I didn't let it to as it would topple again
Right motors have become slow and are not that speedy as compared to the left ones so the quad will finally do a right flip and would end up on its face

Do you think I need to change one of these?

Thanks to this guy I was able to solve my problem..