I still cant get the firmware on my aircraft to update. It fails every time, and I've removed all files from the SD card. Any clue what to do next?

Not sure since I don't know the P3P - but can't you update via the Go app? Under "About" where you see firmware versions?
If you do it manually you want to format the SD card while being in the drone from within the Go app first.
Then you download the firmware from the DJI site, unzip it and copy that .bin file to the SD card OUTSIDE the DCIM folder.

Put the card in the drone, make sure the RC is off and power on the drone. You need at least 2 bars on the battery for that, otherwise it won't do it!
After powering the drone on, the update should be processed automatically.

What do you mean by you still have problems?
If it is this thread you refer to, then perhaps you should have done some replies to that and not start a new thread, starting from scratch with about no information.