ARM boot process

M. Warner Losh imp at
Mon Sep 4 17:52:26 UTC 2006

In message: <44FC3626.701 at>
            Andre Oppermann <andre at> writes:
: I'm new to the embedded system world and have got some Atmel
: at91rm9200 eval boards I'm playing with.  Most of them came
: with Linux and some boot loader to it.
: The supplied boot loaders can't load a FreeBSD arm kernel and
: complain about wrong magic.

Which kernel were you using?

boot0* is to bootstrap the board.  boot0 lets you load an arbitrary
program to execute.  boot0iic allows you to load an image to put in
the iic eeprom (maybe on only on the KB9202).  boot0spi allows you to
load an image into the SPI part.

bootiic is usually what you put in the iic part to boot.  It's fully
functional.  If you have different eeprom parts, you'll need to tweak

bootspi is what I put in the SPI part.  It is presently optimized for
the part that I have, and might need some tweaks.

bootsd will boot off a SD card.  It doesn't quite work yet, there's
some unaligned accesses that I'm still working on sorting out...

: For the at91rm9200 a number of boot loaders are in boot/arm/
: but so far I haven't figured out which one to use.  Eventually
: I'd like to have it boot from the SD card.

That's not yet in the tree.  I'm working on booting off a UFS

I've not looked at integrating the SD support with things like redboot
or uboot yet.


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