BBB boot sequence with xloader and u-boot on an SD card?

GoogleGroups
1

I'm trying to load a non-linux kernel image through u-boot with MLO, u-boot.bin, uEnv.txt and the kernel image on a fat partition on a micro-SD card. With the card installed, on power-up, the console output indicates that the u-boot being used is the one flashed into the eMMC module, not the one on the SD card. I tried holding down the "boot" button and hitting reset, but the result was the
same--not the u-boot on the SD card.

Is there a documented procedure for having BBB reading the SD card first to get the xloader and u-boot before looking at the eMMC device? The only reference I found was to hold the boot button down while applying a reset which did not work.

Thanks,
       Bob

2

http://circuitco.com/support/index.php?title=Updating_The_Software#Image_For_Booting_From_microSD

Gerald

3

Thanks,Gerald. Removing MLO from the eMMC partition caused the boot initiate from the SD card.

Bob Stewart

4

Yep. Works every time.

Gerald

5

Sabi ni Gerald noong Sunday, July 7, 2013 5:55:02 AM UTC+8, Gerald wrote:

Yep. Works every time.

Gerald

Thanks,Gerald. Removing MLO from the eMMC partition caused the boot initiate from the SD card.

Bob Stewart

I’ll have to try it again, but I seem to remember that when I moved the MLO on the eMMC to USB stick, it resurrected itself.

Beaglebone black

6

Just remembered that my 'bone tries to boot off the SD card regardless of whether I hold down the boot button. Doesn’t really bother me, just thought I’d mention it

7

If it cannot find a suitable boot source on the eMMC, that is what it will do. Every time.

Gerald

8

Sabi ni Gerald noong Mon, Jul 15, 2013 at 8:23 PM:

If it cannot find a suitable boot source on the eMMC, that is what it will
do. Every time.

Gerald

Eh? But I *do* have a "suitable boot source", the stock Angstrom.
Haven't touched it, except for uninstalling Cloud9, and even then, it
still boots.

9

If you pull out the SD card, where does it boot from? If you have an SD card inserted that is bootable, it uses the uENV.txt file from that card.

Gerald

10

Even a non-bootable SD card, but with a proper uEnv.txt (i.e. one that u-boot can find and read), may change the boot order. All depends on the contents of that uEnv.txt file. I’m booting wheezy all the time without pressing buttons or having wiped eMMC partitions. – Bas

11

Sabi ni Gerald noong Monday, July 15, 2013 9:45:10 PM UTC+8:

If you pull out the SD card, where does it boot from? If you have an SD card inserted that is bootable, it uses the uENV.txt file from that card.

The eMMC, of course.

Question: if my SD card is bootable but doesn’t have uEnv.txt, what defaults does it use? I seem to have read in another thread that it’ll set video res based on EDID (or something like that, my memory fuzzy at the moment).