[U-Boot] Boot uboot from another position in flash

ich contumax at gmx.at
Wed Aug 3 16:59:00 CEST 2011


Thank for your answer.

> Dear ich,
> 
> In message <1312375799.4776.16.camel at debian> you wrote:
> > 
> > I use u-boot U-Boot 1.3.1 - stm24_0054 for sh (Board mb411) 
> > (STLinux 2.4)
> > It is no problem to boot with u-boot from flash at 0x000000.
> 

I know that. But I am not able to port for sh platform to a newer
u-boot.

> Please note that U-Boot v1.3.1 is about 4 years old and as such no
> longer supported here.
> 
> > But I have to install u-boot in another position in flash than 0x000000.
> > I can also load the uboot from a u-boot loaded in RAM with jtag 
> > (with go  0xa0650000).
> 
> U-Boot is, in it's default configuration, designed to be run on a
> virgin CPU comingg fresh out of reset, so it naturally has to be
> installed at the reset vector of your processor. In addition to the
> start address, many parts of the initialization code expect to find a
> vorgin, uninitialized system.  Such parts must be disabled when you
> want to change the conditions under which you want to run U-Boot.

I read this several time in the net, but found no solution.
I know it is possible, because I saw it in a flash hex-file, but can't
reproduce it.
I thought changing CFG_MONITOR_BASE / CFG_RESET_ADDRESS would do it.

Do you say it's not easily possible to boot u-boot from another flash
address even with a newer u-boot????

Do I have to make big changes to the uboot-source (start.S,..)?

I could put ~256 bytes of assembly code to the reset-vector at
0x0A000000 and jmp in the u-boot; but if you say this is not enough, I
will not start to learn the assembly language for my processor.



Thank you 

        contumax   




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