[U-Boot] No single character output after update to latest u-boot on pandaboard

Chao Xu
2013-11-22T15:29:56Z

Hi Abraham,

Thank you very much for your detailed reply! But I think I can rule
out the three possible problems you mentioned.
1. The cross compiler should be fine. Because I use it all the time to
compile kernel for pandaboard and it has never been a problem
2. I'm doing exactly what you suggested, i.e. the SD card is
partitioned by a pre-built image.
3. The serial cable is fine because the pre-built image was working
properly with the serial cable. Only after I update the u-boot comes
the no-output problem.
Could you think of any other possible problem? I suspect maybe I need
to modify other files (uEnv.txt, boot.scr) in the /boot partition?
These files came along with the pre-built image. Thanks again.

On Fri, Nov 22, 2013 at 3:17 AM, Abraham V.
<abraham.varricatt@vvdntech.com> wrote:
> My company is designing a custom board that can be thought of as a
> derivative of the pandaboard. I believe we have Rev B1 with us in the
> office.
>
> Considering that you are not getting any debug messages on your serial
> console, I suspect one of the following;
> * your cross-compiler might have issues
> * you haven't partitioned the SD card properly
> * your serial cable might be damaged.
>
> Just short the TX and RX lines of your serial cable to test the last point.
> If you can see echo messages, then good, at least the cable is working.
>
> Next worry about the partitions - to boot from SD card, the omap4 on the
> pandaboard expects it in a certain format. Try using pre-build binaries. For
> example;
>
> http://www.omappedia.com/wiki/Android_Panda_Pre_Built
> http://omappedia.org/wiki/Ubuntu_Pre-built_Binaries_Guide
>
> They have instructions on how to format your SD card. Assuming they work,
> then good! Last point is to check your cross-compiler. Just replace the
> existing MLO and u-boot.bin (or u-boot.img; it depends on what version you
> have) on the SD card with your compiled ones and you'll be in a good
> position to narrow down bugs.
>
> All the best,
> Abraham V.
>
>
> On Fri, Nov 22, 2013 at 11:41 AM, Chao Xu <caesarxuchao@gmail.com> wrote:
>>
>> Hi,
>>
>> I'm trying to compile the latest u-boot for my Pandaboard Rev A2. The
>> SD card was originally loaded with a working version of 12.04
>> linaro-unbunt-developer image. Early printk is enabled in the original
>> image.
>>
>> I followed this guide (http://elinux.org/Panda_How_to_MLO_%26_u-boot)
>> and here is what I did:
>> 1. export ARCH=arm
>> 2. export CROSS_COMPILE=arm-linux-gnueabi-
>> 3. make omap4_panda_config
>> 4.make
>> 5. cp MLO u-boot.img /SDCARD/boot/
>>
>> But when switching on my Panda, there is no output from the serial
>> port. And the heartbeat LED is always off. (When every thing works, it
>> is on when booting, and blinks after booting finished).
>>
>> I don't have any former experience with u-boot. So please let me know
>> if there is any more info I should provide.
>>
>> Any help would be much appreciated! Thank you!
>>
>> --
>> Regards,
>> Chao Xu
>> _______________________________________________
>> U-Boot mailing list
>> U-Boot at lists.denx.de
>> http://lists.denx.de/mailman/listinfo/u-boot
>
>

--
Regards,
Chao Xu