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

[Wolfgang Denk]

Dear ich,

In message <1312383540.4776.36.camel at debian> you wrote:
> 
> 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.

Your quoting style is strange.  Normally the reply _follows_.

Well, if you cannot update, then we cannot help it either.  It's yur
problem, after all.

[Well, of course there are companies that will happily send you a
quotation for such an update, in case you are considering a commercial
solution.]

> > 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.

As mentioned, this is NOT sufficient.  See also the FAQ.

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

It is possible, and it is not so difficult if you have sufficient
experience with U-Boot.

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

This depends on your definition of "big".  Judging from the questions
you are asking, I tend to say: too big for you.  No offence meant.

> 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.

This has nothing to do with using assembly code.


Best regards,

Wolfgang Denk

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