I bought 3 of these to fly better in IRL FPV in ACRO mode. I have built 90mm and 100mm quads with 8520 motors. The third FC board serves as a backup. I've spent several hours crashing engines with them and had no problems. Flashed Betaflight SP3 Evo Racing. They come with a decent single sheet layout/manual. Boot/Flash: To get into the boot, I used tweezers to jump over the boot panels. In the Betaflight Flasher I chose the latest version of SP3 Evo Racing. It was pretty easy. Betaflight: I used all the default settings from the version I flashed. except that I enabled engine stop and set engine power to 23000. Motor Schematic: I used Quadx in Betaflight 1/3 CW motors 2/4 CCW motors Receiver: I used flysky FS82 ppm receiver soldered to UART2.FPV/VRX: I directly soldered the battery cables and had no problem. Know the voltage of your fpv/vrx.