Hi. Is it better to downgrade my P4P first before installing new firmware instead of just updating through DJI Assistant? Which device should I downgrade/ update first - RC or Drone, because I read somewhere that someone bricked his RC, because he installed the firmware first on the drone? Thanks!

You do not need to downgrade first. It would be best to upgrade right to the version you'd like to install.

Hi, thank you for  reaching DJI forum. As mentioned above, you don't need to downgrade it first before you update it to the latest firmware version. Kindly check the video tutorial below on how to properly update the firmware using DJI Assistant 2.

Thanks. And about the firmware for the RC I checked Phantom 4 Series Disclaimer and Safety Guidelines v1.2, page 10, section Firmware, point 4 "Be sure to update the remote controller's firmware to the latest version after you update the aircraft's firmware". So to answer my second question: First - update the drone, Second - update the RC.

Clubman Posted at 2018-7-28 05:26
Thanks. And about the firmware for the RC I checked Phantom 4 Series Disclaimer and Safety Guidelines v1.2, page 10, section Firmware, point 4 "Be sure to update the remote controller's firmware to the latest version after you update the aircraft's firmware". So to answer my second question: First - update the drone, Second - update the RC.

That document also say "Be sure to download the firmware package file from the official DJI website", something we can't as it is not there beside for the +controller.

Actually i think the procedure was to upgrade the RC before the AC, that is how it was last year when they implemented the dammed login in app requirement, See the Notes section in this Release note thread.
When Assistant2 works it really shouldn't matter anyway, just use Assistant2 for the aircraft.