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custom u-boot environment

Carmelo Garcia
Prodigy 105 points

Other Parts Discussed in Thread: AM1808

Hello there!

I am working on a project with AM1808, customizing the boot process.

I have placed UBL and u-boot on NAND, with two different options for the linux kernel.

First, u-boot checks the SD for the kernel (like in the LogicPD experimenter kit). I will use this boot mode for system updates with the SD card.

If the SD check fails, u-boot will try to boot the kernel from the NAND.

Now I need to modify the default u-boot environment variables (or even execute a script) to  download the kernel from NFS and write it to NAND if everything else fails.

I have been searching for information on boot.scr, but I have not found how to do this.

Can anyone give me a hand?

Thanks in advance.

  • 0
    Prodigy 105 points

    I have been able to generate a boot.scr writing a textfile with my script and executing:

    mkimage -A arm -O linux -T script -C none -a 0 -e 0 -n 'Flash from SD' -d boot.cmd boot.script

    I still don't know how to get this boot.scr into NAND memory so u-boot can load and execute it.

    In order to enhance the production procedure, it would be easier to save both boot.scr and kernel into NAND memory in a way like u-boot and UBL do with serial flasher.

    Any help on this, please?

    Thanks again.

  • 0 in reply to Carmelo Garcia
    Guru 11260 points

    Carmelo,


    What are you trying to achieve can be achieved by the CONFIG_EXTRA_ENV_SETTINGS option

    provided by the uboot, what I feel you can load the boot.scr in the mmc card in Nand its difficult.

    you can write your own code for it.

    For reference you can have a look at uboot_src/include/configs/omap3_logic.h

    similarly for am1808 , you can modify da850evm.h

    Regards,

    --Prabhakar Lad


  • 0 in reply to Prabhakar Lad
    Prodigy 105 points

    Thanks for your response.

    I had already found that define in u-Boot.

    I did configure it, but when I set environment to defaults, all variables in CONFIG_EXTRA_ENV_SETTINGS do not appear.

    I set environment to defaults with "env default -f", show them with "printenv" and save them to NAND with "saveenv".

    Any ideas of what I am missing?

  • 0 in reply to Carmelo Garcia
    Prodigy 105 points

    Hello again.

    I am still trying to set my own custom default environment variables in u-boot, but CONFIG_EXTRA_ENV_SETTING seems to be useless.

    Is there anything else I should consider to make it work?

    I'm stuck.

    Thanks!