The wiki for allwinner sunxi SOCs states that NAND support is a work in progress and 'have some snippets already'. But that was quite a long time ago and the wiki doesn't seem to have been updated in a while.
I have seen a few patches here and there that seem to have something to do with NAND, but nothing substantial.
Is it possible currently, to build a working NAND image for sunxi boards (specifically the Olimex A20 micro olinuxino)?