Related to APM 2.8

hi I am using APM 2.8 but this time m unable to load new firmware and with complete setup with mission planner also problem in arming.
it is not working with telemetry module also.
pl help me to get the solution.

Don’t waste your time with that obsolete Flight Controller. There are many better choices that run the latest Arducopter firmware.

Solution is simple: Buy a FC that is current. APM is obsolete from a very long time.

If $is a big problem try: Pixhawk 2.4.8
This works without issue with Arducopter 3.6.5