[U-Boot] changes in uEnv.txt does not work

[manish kanchan]

Hi,
I am Manish and i have recently started working on beagleboard xm.
I am facing certain issues. Need guidance to solve it.

Background:
I am using beagleboard xm, uboot version 9 of 2011

Intention:
Current version of uboot has the environment variable loaduimage set for
ext3 partition.Now i want the uboot to pick the uimage from fat partition.
I can do it by modifying the uboot code and use the rebuilt uboot but i
want to remove dependency on building uboot for future version. So i was
trying to play around with uEnv.txt


Exercise:
Initially i tried to update loaduimage to fatload mmc ${mmcdev} ${loadaddr}
uImage and tried booting but was unsuccessful.
I tried to uncover the problem by echo statements to track the code flow.
I observed that the
1.Same command works when i change the omap3_beagle.h and rebuild the uboot
but it does not work if i change it using uEnv.txt.
2.Also that the error is returned from mmcboot->bootm command saying the
image is in wrong format. But i am using the same image as in case 1.

Can some on guide me how do i achive this. I want to use uEnv.txt for
better maintanibilty


Manish Kanchan