On Mon, Sep 8, 2014 at 9:21 PM, Robert Nelson <[email protected]> wrote:
> On Mon, Sep 8, 2014 at 9:04 PM, Jason Lange <[email protected]> wrote:
>> Thanks Robert.
>>
>> Just to be clear, with my currant set up (one ext4 eMMC partition only) the
>> only uEnv.txt that is being used is  /boot/uEnv.txt, and the /uEnv.txt is
>> not functional?
>
> Correct "if" your eMMC has v2014.07 and later installed.. However if
> it's before that version, it needs /uEnv.txt (which will load the
> /boot/uEnv.txt to grab the uname_r/optargs/etc..)
>
>
>>  But if it was on an SD card and was inserted into a board
>> that had been flashed with Angstrom the /uEnv.txt would allow the SD card to
>> boot?  Even as an SD card with ext4 only?
>
> Yeap.. That u-boot is looking for /uEnv.txt using the generic "load"
> command, so it doesn't care if its fat/ext..
>
> There's really only 5 variables we need to update for that very old u-boot:
> https://github.com/RobertCNelson/omap-image-builder/blob/master/tools/setup_sdcard.sh#L626
>
>>
>> If the above is true, would my /boot/uEnv.txt be seen at all? (that is
>> booting from the SD card on an Angstrom
>>  flashed board)
>
> With my custom /uEnv.txt that i flash by default it'll load /boot/uEnv.txt
>
> I know it's odd, /uEnv.txt loads /boot/uEnv.txt  ;)
>
> I was just hacking away and that's what happened, for awhile it was
> /boot/extlinux.conf but we are not ready to make that big of a jump
> yet..

btw, the whole point of this change.

The location of *.dtb was never standardized.. Right now there are 3
competing locations.. Ubuntu just elected to follow fedora's..

Mainline works fine..

So i'm setting up the bootloader to boot anyone's kernel, by just
passing uname_r to u-boot..

u-boot is literlly searching these locations:

http://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0#u-boot_dtb_search_order

when it finds the *.dtb it'll boot it..

This also allows us to switch between mainline, ubuntu, debian
kernel's in teh same image.

the *.deb package places the *.dtb in the location that distro wants,
and we just update uname_r in /boot/uEnv.txt

Regards,

-- 
Robert Nelson
http://www.rcn-ee.com/

-- 
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