The original YAFFS(1) code (the stuff in this directory) is pretty much
obsoleted and unmaintained, although thought to be reasonably stable.

You'd most likley be far better off using the YAFFS2 tree which can support
512-byte page NAND in a backward compatability mode.

YAFFS2 gets all the attention these days and very few changes are made to
the original yaffs tree.