setenv x_bootcmd_kernel 'ext2load usb 1:1 0x6400000 /boot/uImage'
saveenv
To determine 1:1 in the command above
usb start
usb part
## Unknown partition table
## Unknown partition table
Partition Map for USB device 2 -- Partition Type: DOS
Partition Start Sector Num Sectors Type
1 63 14586957 b
2 14587020 1060290 82
here you have device 2 and you want to boot Partition 1 so use 2:1 (as opposed to 1:1 in the command above).
While still under the bootloader , check your environment with ''printenv''.