How to enable external compass or magnetometer on APM 2.8

APM 2.8 is not an original board and is a modified clone which is made by Chinese manufacturers. It has an internal compass and can connect external compass. I searched a lot on the internet for enabling the external compass and disable the internal compass. it has some difference than APM 2.5 which also comes with the internal compass because we need to cut the PCB trace to disable its internal compass. But in 2.8 it only needs to change a jumper configuration. And in some cases we cant activate its external mag by changing this J2 jumper. For these situations please follow this instruction to enable external compass which comes with the GPS module. Please don't forget to Subscribe and hit the like button. Thank you.