Can I restore a nand backup of ZVC with fastboot over version ZVE?
No because you will be going from a 2.2 back to 2.1
It will boot loop you.
If you want to do this you will have to use death2all110's guide to take you back to zv6
And if you made a nandroid and had fastboot then, you should still have it. Given that the nandroid was made on your phone and you didnt use LGMU to upgrade at any point.
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