[U-Boot] [u-boot]automatic reset of variables to defaults

Marek Vasut marek.vasut at gmail.com
Thu Nov 17 19:26:09 CET 2011


> Hello u-boot users list,
> 
> I am experiencing a problem concerning variables being set and later
> getting lost.
> 
> In order to boot a Linux on a quite small plattform (Eddy CPU:
> http://sysbas.en.ec21.com/Embedded_CPU_Module--1904028_1904479.html ), I
> have to reset the variable "OS_SDRAM" from its initial value of
> "0x20000000" to "0x21000000". If I don't do so, the bootloader reports
> problems extracting my kernel. This must be due to my kernel being
> bigger than expected by u-boot.
> 
> These are the steps, that I take:
> 
> [code]
> setenv OS_SDRAM 0x21000000
> saveenv
> reset
> [/code]
> 
> Anyway, this way, it works fine.
> 
> Sometimes, the bootloader looses this configuration and resets its
> variable "OS_SDRAM" back to its default value. Once, the bootloader has
> reset this value, it cannot boot anymore(well, of course not, since I
> had to manually alter this value in order to make it boot my linux).
> 
> Annoyingly, I cannot surely reproduce this error. I tried rebooting it
> over 3 days in 2-minute-steps and the error won't occur. In addition, I
> tried giving random input to the console of u-boot for 3 days (again in
> 2-minute-steps) and still the error won't come up.

Probably something's overwriting your uboot in ram. Anyway, is the board 
supported mainline?

> 
> Two questions:
> 
> 1. What else might be the cause of this?
> 
> 2. How could I prevent u-boot from resetting to its default value?
> 
> I'd be happy for any kind of help.
> 
> Best regards,
> Dennis

Try getting mainline support for the board, that way you'll have the latest 
fixes.

M


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