The Radio dongle can be programmed either via USB bootloader or via SPI. The USB bootloader does not require any hardware but is not currently (as of 2012-09) full-proof (if the flash procedure does not complete well the dongle will have to be reprogrammed via spi). Unless you have equipment to re-flash the dongle via SPI (currently requires a JtagKEY jtag interface), program only Bitcraze released firmware via USB (last firmware image can be found there).

In Linux it might be required to launch the commands accessing the USB port as root (ie. with sudo). Also the scripts are written in Python2 so if you distribution has python3 by default replace python by python2 in the commands.

First Crazyradio has to be rebooted in USB bootloader mode. To do so insert the dongle in the pc, open a terminal window and run the bootloader launcher:

> cd crazyradio-firmware
> python usbtools/launchBootloader.py 
Launch bootloader .
Bootloader started

After running this tool the Crazyradio dongle should have disappeared and a new device named nRF24LU1P-F32 BOOT LDR should appear.

To flash the firmware use the nrfbootload.py script:

> cd crazyradio-firmware
> python usbtools/nrfbootload.py flash cradio-0.51.bin
Found nRF24LU1 bootloader version 18.0
Flashing:
  Flashing 5771 bytes...
Flashing done!
Verifying:
  Reading firmware/bin/cradio.bin...
  Reading 5771 bytes from the flash...
Verification succeded!