[U-Boot] How to test a new u-boot image over network?

[vikas.sontakke at emc.com]

Hi Anatolij,

Before I attempt to burn the new image in the flash, I want to test it first.  There are instruction on burning this image in to flash but 

The documentation that I am looking says following:-
==========================
"If U-Boot is already installed and running on your board, you can use these instructions to download another U-Boot image to replace the current one.

ALERT! Warning: Before you can install the new image, you have to erase the current one. If anything goes wrong your board will be dead. It is strongly recommended that:

    you have a backup of the old, working U-Boot image
    you know how to install an image on a virgin system

ALERT! Proceed as follows: "

<<The rest of the instructions are for burning it in the flash.>>
===========================


I am complete newbie at this.  I also tried "go <load_address>" but that caused immediate crash.

I am hoping that this is trivial for somebody who has updated u-boot code.  If I am using wrong command, please tell me correct command to test the u-boot from RAM before burning it to the flash.

Thanks,
- Vikas


-----Original Message-----
From: Anatolij Gustschin [mailto:agust at denx.de] 
Sent: Wednesday, December 07, 2011 2:59 PM
To: Sontakke, Vikas
Cc: U-Boot at lists.denx.de
Subject: Re: [U-Boot] How to test a new u-boot image over network?

Hi,

On Wed, 7 Dec 2011 12:41:38 -0500
<vikas.sontakke at emc.com> wrote:
...
> 
> uboot-sources-EMC/u-boot-2009.01> file u-boot.bin
> u-boot.bin: u-boot/PPCBoot image
> 
> uboot-sources-EMC/u-boot-2009.01> mkimage -d u-boot.bin u-boot.bin.load
> Image Name:
> Created:      Wed Dec  7 12:08:45 2011
> Image Type:   PowerPC Linux Kernel Image (gzip compressed)
> Data Size:    393216 Bytes = 384.00 kB = 0.38 MB
> Load Address: 0x00000000
> Entry Point:  0x00000000
> uboot-sources-EMC/u-boot-2009.01>
> 
> 
> I then tftp the image "u-boot.bin.load" and bootm it but I am getting following error.
> Error: Bad gzipped data
> GUNZIP: uncompress or overwrite error - must RESET board to recover

Did you read the documentation? Why are you trying to
boot U-Boot image using 'bootm' command? 'bootm' command is
used for booting operating system images.

If you want to update U-Boot on the board, you need to write
it into the flash memory used for booting. Do you have a
JTAG debugger for the case updating U-Boot image goes wrong
for some reason?

> I have tried many different load addresses such as 0x40.0000,
> 0x400.0000, 0x800.0000, 0x1000.0000.  with exactly the same
> behaviour.  What am I missing?

Please read U-Boot documentation [1] to understand which
command is used for which purpose. Updating U-Boot is
also described in the U-Boot documentation.

HTH,
Anatolij

[1] http://www.denx.de/wiki/view/DULG/UBoot