Boards have been shipped with various versions of Cleanflight or Betaflight as development has progressed. I'd recommend installing the latest version of either one from the links above when you receive a new board.
Installing New Firmware
Cleanflight Configurator version 1.0 and later includes support for the DFU USB interface on the STM32F3 CPU. This allows flashing any board that uses the built-in USB port.
Download the preferred betaflight_MOTOLAB.hex or cleanflight_MOTOLAB.hex from the links above.
IMPORTANT NOTE: For Zadig driver installation, be sure to plug in the board with the boot jumper shorted to make it appear as a DFU BOOTLOADER device. Do not allow the Zadig program to install a driver for an STM32 Virtual Comm Port device.
Computer setup: Windows needs a driver for the STM32 in bootloader mode. Linux needs a udev rule and your user ID must be added to the dialout group. The...Continue Reading
The MultiWii_MotoWii_RevB_V3 contains a folder called "MultiWii_MotoWii_RevB_V3". To open the sketch in arduino, browse into that folder and select the file "MultiWii_MotoWii_RevB_V3.ino". Make sure you're in the right place.
config.h should be the only file you need to edit. The only changes you'll need to make might be:
For Spektrum-compatible satellites, the radios may bind at either 1024 or 2048 resolution. The sketch is set for 2048, but if your receiver channels seem scrambled you may need to change #define SPEKTRUM 2048 to #define SPEKTRUM 1024.
To switch from Spektrum satellite to a PPM_SUM receiver, comment the #define SPEKTRUM line and uncomment one of the #define SERIAL_SUM_PPM lines that corresponds with the channel order in your transmitter.
To enable 125uS onshot mode on the KISS ESCs, uncomment #define ONESHOT. You'll need to short the J1 jumpers on the ESCs too for this.