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

[Abraham V.]

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 at 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
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