I think you can edit the bootloader to recognice two different keys during boot (select for one, start for the other), and, based on that key, to look for different kernels. And after that, reflashing your device with that new bootloader and puting both kernels in the SDCard with the proper names.
Anyway, I've never seen any code of dingux or the bootloader, so I'm not even sure if this is possible. Better wait for more info before trying anything I said
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