[U-Boot] Read uEnv.txt from EXT4 partition

I am running U-Boot 2013.01-05972-gd80f33a. When I power the board I get:

** Unrecognized filesystem type ** 206 bytes read in 21 ms (8.8 KiB/s) Loaded environment from uEnv.txt ** Unrecognized filesystem type ** ** File not found boot.scr ** ** File not found boot/boot.scr ** ** Unrecognized filesystem type ** uboot#

So I issue these commands:

setenv bootargs 'root=/dev/mmcblk0p1 rw rootwait=3 console=ttyS0,115200n8 loglevel=7 mem=256M@0x40000000' ext4load mmc 0 0x43000000 /boot/script.bin; ext4load mmc 0 0x48000000 /boot/uImage; bootm 0x48000000

And the system boots as expected. So I know that uboot can read from my EXT4 partition. Is their any way to change the default filesystem type from FAT or change the default boot scan to search for uEnv.txt in /boot as well as different filesystems?

Thanks!