First get the latest hex file (=the firmware) using wget. The output file will be named baseflight.hex and may overwrite any other file having the same name.
wget http://afrodevices.googlecode.com/svn/trunk/baseflight/obj/baseflight.hex -O baseflight.hex
Next attach the usb cable to the board and if unsure check with dmesg that the device was detected. The output will look something like this.
usb 7-2: new full speed USB device using uhci_hcd and address 8 usb 7-2: configuration #1 chosen from 1 choice cp210x 7-2:1.0: cp210x converter detected usb 7-2: reset full speed USB device using uhci_hcd and address 8 usb 7-2: cp210x converter now attached to ttyUSB0
In my case, the board was attached to ttyUSB0 so it can now be accessed with /dev/ttyUSB0. There are two ways of setting the serial port settings and activating the flash mode. The first one consists of two command:
All three leds in the board should now be lit. Alternatively, for example CuteCom can be used for sending the R letter. Be sure to set the baud rate to 115200 before opening the device. Note that “No line end” needs to be selected.
Now you can proceed with the stm32flash command:
stm32flash -w baseflight.hex -v -g 0x0 -b 115200 /dev/ttyUSB0
The output should look something like this:
stm32flash - http://stm32flash.googlecode.com/ Using Parser : Intel HEX Serial Config: 115200 8E1 Version : 0x22 Option 1 : 0x00 Option 2 : 0x00 Device ID : 0x0410 (Medium-density) RAM : 20KiB (512b reserved by bootloader) Flash : 128KiB (sector size: 4x1024) Option RAM : 15b System RAM : 2KiB Wrote and verified address 0x08009d68 (100.00%) Done. Starting execution at address 0x08000000... done.
Powercycle the board and access the version string from the terminal. It should now be updated.