[U-Boot] modifying u-boot image to distinguish between primary and secondary

[Ravi Shekhar]

Sorry for not providing with more details. On my board I have a primary 
(recovery) bootloader and a secondary full-featured bootloader.  The 
primary bootloader is normally not interactive or accessible at startup. 
The primary bootloader immediately loads the secondary bootloader.  If the 
secondary bootloader is corrupted (its checksum fails) then the primary 
bootloader will become interactive and place a <RECOVERY-BL> prompt. 
Normally, I burn primary u-boot image first and then I get a recovery 
console from where i burn secondary u-boot to flash. Now, My idea was to 
append some string to the version of the u-boot and some how parse it 
before loading it then I can distinguish between the two u-boot images. As 
I am new to u-boot, I wanted to know whether this approach is right or 
not. This is required only to prevent user from using wrong u-boot image 
for booting (say, using secondary image instead of primary).

--Ravi






Wolfgang Denk <wd at denx.de> 
01/25/2010 01:53 PM

To
Ravi Shekhar <Ravi.Shekhar at Lntemsys.com>
cc
u-boot <u-boot at lists.denx.de>
Subject
Re: [U-Boot] modifying u-boot image to distinguish between primary and 
secondary






Dear Ravi Shekhar,

In message 
<OFFE8B8C82.0B75DDB4-ON652576B6.001CDB45-652576B6.001D0D2F at lntemsys.com> 
you wrote:
>
> My board has two boot-loaders namely, primary bootloader and secondary 
> bootloader. however the image file name for both the bootloaders are 
same, 
> u-boot.bin. Now, I want to make a check before loading u-boot to flash 
> whether its a primary bootloader or secondary bootloader. What i thought 

> is, why not to append primary or secondary string after the version in 
the 
> uboot..bin but I am not sure how it works. Can anyone please give me 
some 
> Ideas on this.


You have to be more specific.

Why do both your images have the same file name? Wouldit not besimple
enough to rename at least one of them?

I understand the images are different (otherwise changing the version
string would not work).

You write "check before loading u-boot to flash" - in this case, how
does modifying the version string inside the image help you? You
would need a tool to "look inside" the images so it can locate and
extract this string.

Assuming you are using U-Boot to load the images and write these to
flash, you might create U-Bot images (using mkimage with "-T firmware"
and "-O u-boot") and use these. Here it is trivial to assign names to
the images, which can easily be extrated (using "mkimage -l" on the
command line or "iminfo" in U-Boot).

Or, with a little more effort, but a lot additional flexibility, you
could create a single FIT image which holds both your primary and
secondary image, so these can be installed in one go.


If I were you I would try the FIT image approach.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
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Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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