Reviving an old thread to post what I found:
On my Omega 2+, the uboot environment seems to start at 0x2000 in /dev/mtd1, and runs to 0x5fff, thus my /etc/fw_env.config files looks like:
# Configuration file for fw_(printenv/saveenv) utility.
# MTD device name Device offset Env. size Flash sector size Number of sectors
/dev/mtd1 0x2000 0x4000 0x1000