I tried the above and it worked, if you have the time, try it to and let me know how it goes!
Well, perhaps you can backup your uboot, but it seems that you can't write it back this way:
# mtd write u-boot.bin mtd0
Could not open mtd device: mtd0
Can't open device for writing!
You can, but it's not as trivial, so it requires some hoop jumping to get it done.
# mtd write u-boot-env.bin u-boot-env
Unlocking u-boot-env ...
Writing from u-boot-env.bin to u-boot-env ...
# mtd write u-boot.bin u-boot
Unlocking u-boot ...
Writing from u-boot.bin to u-boot ...