I need help! 

I have a Falcon 180 from Eachine, that rotated the FC 90 degrees. I changed that in attitude in libre pilot and updated the firmware. Props are on correct motors spinning correctly also. But it flips on take off.

But the motor was stuttering. When I checked I found one wire broke so I just re soldered it, however I am still having same problem

1) make sure that the offset for FC rotation you changed is YAW
2) if the usb port is to the left, its usually -90 if its to the right its usually 90 degrees. you check that by doing the modification pressing save, and going to the general tab to see if the graphic represents trully what you do with the quad without powering it on

Also check out some other troubleshoot tips from this post

Make sure the motors are connected to the correct port on the flight controller. Check this on the motors tab and spin up one motor at a time to confirm.