I have a Phantom 4 but haven't operated it for some time. I charged the batteries etc.  but then found the controller would not connect to the drone. I thought it may be an update issue so I downloaded the latest DJI Assistant 2 to my PC, and DJI Go 4.
Issue 1: DJI Go 4 indicated there was an update for the controller which I attempted to install. I don't know what I did, but when I checked to make sure the update was successful it indicated I now have Firmware 1.8.0 for a Phantom 3 Pro, with no option to reset or update the controller firmware to Phantom 4. Please help me to get back to Phantom 4 firmware.



Issue 2: DJI Assistant 2 indicated there were two updates for Phantom 4. I selected the latest and started the update process. The update downloaded and then started to install. The install got to 99% then hovered for a few seconds before failing. I retried the install multiple times but it failed each time. I have read many articles on the internet, tried a couple of the suggested fixes, but always ended up failing to update. Is there a "solid" method to ensure the update succeeds? Please help.

I would appreciate any help you can offer, and understand these issues may need to be tackled one by one. Thank you.

The first thing to check is that there is communication between the aircraft and the RC (the display device does not need to be connected at this stage).

So when the P4 and the RC are both powered up, is the first LED on the RC green ?

If it is then that is a good indication that the communication between the P4 & RC is good.
If it is red, then that is an indication that the RC and P4 devices need to be relinked (in a similar fashion to pairing bluetooth devices).

Aardvark Posted at 2-8 22:59
The first thing to check is that there is communication between the aircraft and the RC (the display device does not need to be connected at this stage).

So when the P4 and the RC are both powered up, is the first LED on the RC green ?

Thanks for responding. The light on the controller is solid red.
Relinking is not something I've done before. I checked the manual and it says to enter "Camera" and tap on the controller icon. Problem - how to enter "Camera"?

DrRay Posted at 2-9 00:05
Thanks for responding. The light on the controller is solid red.
Relinking is not something I've done before. I checked the manual and it says to enter "Camera" and tap on the controller icon. Problem - how to enter "Camera"?

Have a look at DJIs video

Aardvark Posted at 2-9 01:23
Have a look at DJIs video

https://www.youtube.com/watch?v=jPdlE_zKWYk

Thank you for the video.
The P4 and controller linked after a couple of tries.
On the DJI Go 4 screen the Aircraft Status shows updates required, so I followed the update instructions with no problems. To the right of that Äbnormal" in red text. I tapped on that and the next screen showed a "Gimbal Calibration Error". In the Overall Status screen it shows 2 messages -
"Gimbal joint angle sensor initialization error"; and
"Gimbal Calibration Error".
For both errors it suggested restarting the P4. I did this several times, but still have the same error messages.
The option provided was to contact DJI support.
Do you know if there are other things I can do to fix this.
Really grateful for your help.
BTW I'm in Australia, so my responses may be delayed by time zone differences.

DrRay Posted at 2-9 15:21
Thank you for the video.
The P4 and controller linked after a couple of tries.
On the DJI Go 4 screen the Aircraft Status shows updates required, so I followed the update instructions with no problems. To the right of that Äbnormal" in red text. I tapped on that and the next screen showed a "Gimbal Calibration Error". In the Overall Status screen it shows 2 messages -

You could try calibrating the gimbal, see @ 3:30 in this video:-

Thank you for your response.
I followed the video and used the automatic gimbal calibration successfully.
However, I am still getting the  same error messages ...
"Gimbal joint angle sensor initialization error"; and
"Gimbal Calibration Error".
I tried turning both the controller and the P4 off and rebooting them both, and still get the messages.
Also got another message "Battery Cell Damage". The battery had been fully charged previously.
I have a feeling that the DJI Go 4 app is not talking to the P4 properly.
I keep trying to update the P4 firmware thru DJI Assistant 2 for Phantom - keeps failing.
I need to go to a client's site for the next few days and will have no internet connection.
Thank you for your help. I'll continue when I get back.

DrRay Posted at 2-9 23:38
Thank you for your response.
I followed the video and used the automatic gimbal calibration successfully.
However, I am still getting the  same error messages ...

Have you a different battery you could try ?

Check that there is no dirt or grit obstructing the gimbal movement in any way, also check by hand and move gimbal side to side and back and fore, to make sure the gimbal is seated properly in the rubber bush at bottom of aircraft.

With all powered up, when you look at 'About' which is at the bottom of the 'General Settings' menu in DJI Go 4 it should list all the current firmware in use. I have seen in the past where updates seem to 'stop' at 99%, and it would seem that it is complete but not being reported correctly by the system. If I remember correctly the progress pauses for a while at certain points during and at the end of firmware update to aircraft. So give it a few minutes at the end to be sure.

Also a good idea to check and make sure you are running the latest updates on DJI Go 4, and Assistant 2 which can be gotten from HERE (That page is a good bookmark for the P4 if you don't have it).

Also worth bearing in mind that there can sometimes be conflicts between DJI Go 4 and the didplay device used, more often than not if it's Android based.