If you have never flashed your sideboard before, the MCU is probably locked. The 3V3 can be either obtained by connecting the pin to the ST-Link programmer or powering the sideboard with 12/15V. Connect GND, SWDIO and SWCLK to your ST-Link V2 programmer. On the sideboard, there is a debugging header with GND, 3V3, SWDIO and SWCLK. Of course the firmware can be further customized for other needs or projects. VARIANT_HOVERBOARD: In this variant the sideboard is communicating with the mainboard of a hoverboard using the FOC firmware repository.
HOVERBOARD GYROSCOPE SERIAL
An RC receiver with iBUS protocol can be connected to the AUX serial Rx pin (see schematic)
![hoverboard gyroscope hoverboard gyroscope](https://www.rmt-scooter.com/Content/uploads/2020642526/202006171529200b7ce738378347d6ac90d897d435e52e.jpg)
► If you have an STM32 sideboard check-out the repo hoverboard-sideboard-hack-STM The hoveboard comes with two identical sideboards that can be flashed with this firmware. This repository implements the firmware for the hoveboard sideboards.