This page describes how to recover a board using DFU mode, this procedure only applies to DFU capable devices like Revolution, RevoNano or Sparky2 boards.
Unfortunately, the CPU used on the CC3D flight controller does not support the DFU bootloader, see this page instead. Note that the page seems to be unviewable now and you may need to view it on archive.org.
During production of the STM32 micro-controller, a low level bootloader is programmed into the device as part of the process. One of the serial communication interfaces on which this bootloader is available is the USB port and it supports the DFU protocol.
The only hardware required is your flight controller and a USB cable.
In this page
Prepare board for DFU mode
You need to short the two SBL pads in your flight controller.
Pictures below show SBL pads location for Revolution, RevoNano and Sparky2 boards:
Be careful, in some cases there is others components around.
Put a solder joint only between the two pads!
After is done the controller will show only one led on (the power led) and the other leds do not blink anymore because the internal boot loader does not control it at all.
Install Zadig driver (windows)
After you connect your DFU device to the computer, a window pop up ask for a driver install.