I think you may be confused as to what u-boot variables is.
I presume you have ANDROID on your BOX (Nand)
When you Flash the OpenELEC SD Card version the uboot variables are set DURING THE First Initial Flash. .
This means that every time (after this once off flash) you turn on the box with the SD Card inserted THE BOX WILL BOOT TO OpenELEC.
If you take out the SD Card and then turn on the box It will Boot Into Android.
If you power off Box and then insert SD card. Then power on the box . It will Boot Into OpenELEC.
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