On Sun, Jan 25, 2015 at 6:48 PM, Robert P. J. Day <[email protected]> wrote:
>
> again, just some pedantry and making sure i understand the search
> order here, if i create a new SD card for my BBB with nothing but raw
> MLO and u-boot.img images dd'ed to card (no partitions), then boot,
> what i see is:
>
> ...
> switch to partitions #0, OK
> mmc0 is current device
> gpio: pin 54 (gpio 54) value is 1
> ** No partition table - mmc 0 **
> Checking for: /uEnv.txt ...
> ** No partition table - mmc 0 **
> Checking for: /boot.scr ...
> ** No partition table - mmc 0 **
> Checking for: /boot/boot.scr ...
> ** No partition table - mmc 0 **
> Checking for: /boot/uEnv.txt ...
> ** No partition table - mmc 0 **
> ** No partition table - mmc 0 **
> ** No partition table - mmc 0 **
> ** No partition table - mmc 0 **
> ** No partition table - mmc 0 **
> ** No partition table - mmc 0 **
> ** No partition table - mmc 0 **
> ...
>
> technically, that makes sense, mmc0 above represents the SD card and
> u-boot would seem to be looking for uEnv.txt first in a partition on
> the SD card but since i have no partition at all, it will fail. but
> (and this is admittedly more a u-boot question), is there any reason
> that u-boot can't just notice there's no partition and not spend all
> that time trying over and over looking for different files, since all
> of them will fail? it's not wrong, it just seems inefficient.
Last i checked, there wasn't a check for partition existence in u-boot.
For /uEnv.txt/boot.scr/boot/boot.scr/boot/uEnv.txt It's just use the
"file existence" check before trying to load it.
if test -e mmc ${bootpart} /uEnv.txt; then
> also, to follow up on my earlier question, it looks like, if i want
> to add nothing but uEnv.txt to the mix, i can create that ext4
> partition on the card, then populate it with *nothing* but
> /boot/uEnv.txt, is that correct?
All you need in t /boot/uEnv.txt is a variable:
uname_r=
(kernel: uname -r syntax)
Unless your also using the eMMC, then it's really best to have:
uuid=
http://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0
Regards,
--
Robert Nelson
http://www.rcn-ee.com/
--
For more options, visit http://beagleboard.org/discuss
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