Only use this type of firmware flashing if you crazyflie is not booting up properly. Check the cfclient userguide for the official instructions.
For updating the Crazyflie firmware there's the possibility to enter bootloader mode and flash new firmware from within the client. The bootloader mode is accessed from the menu Crazyflie->Bootloader. If there is any problem during the flashing or a wrong firmware is flashed the process can just be started again.
To update the firmware in the Crazyflie 2.X do the following:
- Make sure that the Crazyflie is disconnected from the client and powered off.
- Go to the menu Crazyflie->Bootloader
- Select the "Cold boot (recovery)" tab in the dialog.
- Hold the button for about 3 seconds when turning it on until the blue LED M2 starts to blink to get into bootloader mode. If a wrong nRF51 firmware has been flashed you might have to start from an un-powered state. Then hold the button and connect power.
- Click "Initiate bootloader cold boot"
- Select the latest release from the drop down menu or select it if you have downloaded it from the Github release page.
- Press "Program" and wait (do not restart the crazyflie untill it is finished.)
- Press "Restart in firmware mode"
Be aware that the Lighthouse FPGA will not be updated in this mode, so please use the the cfclient userguide after you have recovered crazyflie.