> For the complete documentation index, see [llms.txt](https://principiot.gitbook.io/principiot-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://principiot.gitbook.io/principiot-docs/f7/important-notes.md).

# Important Notes

Here a few key things to keep in mind:

* The flight controller comes preflashed with Betaflight 4.5.1 with the Crossfire radio protocol and DSHOT motor protocol. **For use with any other receiver or motor protocol, the Betaflight firmware will need to be reflashed.** This is an easy process, see the Flashing section below for instructions.
* The onboard connectors are compatible with the JST SH 1.0mm connector series. If you need additional mating connectors, connector kits can be purchased on Amazon with pre-crimped terminals. Customized cable harnesses are available with larger orders. For more information on OEM integration, contact <info@principiot.com>.
* All data pins (UARTs, I2C, SPI, LED strip, etc) are 3.3V tolerant. Do not apply more than 3.3V to the pins or you may damage the processor.
* When powered over USB, only the receiver and GPS 5V ports are powered. The other 5V systems are only powered when running from battery power.
* The 3.3V supply is limited to 600mA and shared with the main processor. Don’t pull more than 300mA from this pin, otherwise you may damage the flight controller.
* **Do not power the flight controller with more than 26V or it may be damaged.**
* The ESC telemetry pin is shared with the UART 6 peripheral. If using ESC telemetry, UART 6 can’t be used for another purpose.