Dear All,
I am trying to implement an automatic firmware upgrade functionality on a U-Boot / embedded Linux board the following way. If anyone has done something similar before, please, comment if this is the right approach to the problem or I should choose a different solution? The hardware is a BeagleBone Black acting as the DFU device (to be updated). It is connected to a host machine (PC) that downloads the new firmware using USB DFU.
So, here are my planned steps for DFU fw upgrade.
1) A U-Boot environment variable is set from embedded Linux if a fw upgrade is required. Then the board is rebooted.
2) In the boot-up script, U-Boot checks the value of the environment variable and enters DFU mode instead of booting the Linux kernel. This command is executed to enter DFU mode: 'dfu 0 mmc 0'.
3) At this point the host recognises the DFU device and downloads the new firmware image.
4) After the download has finished, the environment variable is reset to indicate normal boot and the board is rebooted.
5) Board boots up using the new firmware.
When tested this manually, I found a problem in step 4) because U-Boot requires pressing Ctrl+C after the download finished. This suggests me that DFU can't be controlled by a script as I described above. Is this correct? What is the idea behind waiting for Ctrl+C and not returning immediately? Any comments or hints are appreciated.
Thanks, -Tamás