[U-Boot] SPL Dfu update

[Wolfgang Denk]

Dear Michael Trimarchi,

In message <CAOf5uw=hCkwPaqogCO3KvM1erhS-dvC5BRT4USU3uqKETtTQ7A at mail.gmail.com> you wrote:
> 
> > This does not answer Stefano's question: why do it in SPL, what's
> > wrong with loading the real U-Boot for this purpose?
> 
> Because it's not possible, internal memory size of some cpus. You need
> to have a way to load the second stage and I'm discussing a general
> way to do.

I'm not sure that there are many use cases where you have sufficient
room for all that is needed for DFU (including I/O buffers); and if
you move to RAM early, you have other options as well.

> What is your alternative way?

Depending on your hardware there is a zillion ways to do this.  For
low to medium volumes good old JTAG is still a very powerful tool; for
high volumes you will probably just fit pre-programmed NAND on your
board.  And of course there is the growing number of systems that can
just boot and install from a SDCard or USB MSD.

Best regards,

Wolfgang Denk

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