I just got my Phantom 4 second hand.

Everything seems fine, except I've found that the remote is in mode1, I want it in mode 2 (Z/yaw on left joystick, X/Y on right).

I've been Googling around and found that P4 stick functions can be set with the DJI Go app on my Android phone, so I installed and ran it, and sure enough it was set to mode1.  I set it to mode2 and had another go at flying the drone outside - and immmediately crashed it, busting two propellers. Ran the DJI Go app again, and it's saying mode1 again.

Now I know that DJI Go is not lying, my crash proves that.  So is there a "Save changes" somewhere that I missed?

p.s. The remote is a GL300C, in case there is more than one used by the P4.

Really sorry to hear the crash, may I know everything functions well except for two props?
When change the settings, you must make sure all devices are connected properly, and double check the result after changing any parameters.

Hi, thank you for the reply.  The only thing that got damaged other than the props was my pride!

I'm pretty sure all devices were connected properly, because the app told me that both needed firmware upgrades. I completed the firmware upgrade on the transmitter, but decided to leave the P4 update until after my test flight. I did double (and triple check) the mode1/mode2 setting after the change. It was fine until I switched off the transmitter and the DJI Go app on my phone.

[..later]

Success!  I thought that for due diligence I really ought to try once more, but this time I used a Nexus 10 Android tablet I just brought back to life (new battery, new install of Android 6.0 Marshmallow). The DJI Go app worked perfectly on the tablet, it configured the transmitter (which acknowledged by beeping), then I took the P4 for a successful test flight, even with two props shorter than the others!

In hindsight: is it possible that I was using an old version of the DJI Go app, i.e. pre-P4?  Perhaps the configuration block format in the P4 has changed from earlier versions?  You're going to ask me if I used the QR code in both cases to find the app, and I must honestly answer that I don't remember. I'm new to smartphones (and it's a new phone) and didn't have a QR reader app right away. I may just have searched Google play for "DJI Go" and taken the top hit. Not smart!

Note for other noobs like myself: if you don't hear a beep beep acknowledgement of the change from the transmitter, it didn't change!