Serial UART boot protocol on IMX25, what is the structure of an application image?

ElanDoensen · ‎11-13-2011

We are using imx257.

The freescale ATK did was not reliable and refused to work with our imx257 board (The ATK passes the POS test). Thus I wrote a tool to use the "serial download protocol" to blow the fuses of our board and get it to a state that it could boot from MMC or SPI flash. It can also be used to read/write memory etc.

Problem is that if we blow the fuses on the imx to boot from SPI, if we ever mess up the SPI flash, we are left with a bricked unit. However when the SPI flash is messed up, the HAB on the imx defaults to "serial download protocol" and we can talk to it.

I need the ability to make the imx (using the serial download protocol) run an application (specficially a uboot image) that I can load into dram. I can then use that application to fix the SPI flash.

According to the imx257 documentation, it is possible to load and run an application via the serial download protocol. (Chapter 7.8). However I have tried to do this and have failed. Problem is I am uncertain what form the application image must take.Does it need a flash header? Does it need a DCD? How does it jump to the application when you download it? This is completely unclear from the imx manuals that I have.

Can anyone give some hints on how the application image should be structured for the imx to run it from the serial download protocol?

qiang_li-mpu_se · ‎11-21-2011

Maybe you can try the MFGTool for iMX25: http://imxcommunity.org/group/manufacturing-tool-mfgtool

The tool will download the runtime uboot, kernel and RAM rootfs onto the board and run it, you can replace the uboot with your own one.

Same as the ATK tool, before download the runtime image, the memory need be initialized first, you can check the odcuments for how to modify the MFGTool for your board.

For IMX25 boot, if the boot device is SPI but there is no boot image on it, the IMX25 will boot to download mode automatically, then you can use the MFGTool to run your image on the board to repair it.