My P4 crashed and the gimbal and camera are toast. It wouldn't connect to dji go 4 after that it told me I had a P3 and needed to download older software. Went to assistant 2 it said to update but the update crashed. When I reopened assistant 2 it said can't read firmware. The factory reset failed 4 times. Any help would be appreciated.  It did open with litchi for the P4 but battery information was N/A.

Time to see the DJI Doc.

I wanted to see if imu's and compasses are OK.  I want to see if it flies OK too.  Just want to sell it as is but wanted to be able to check things out so I could give some information on the P4.

If it's not able to perform a factory reset or reapply the firmware after the crash, the main controller is most likely damaged which would require sending it in for service.