Mr Manning,
> You certainly can use YAFFS under Linux without mtd - some people have done 
> this already. YAFFS does all its NAND accesses via four functions. If you 
> provide functions that access the NAND directly then things will work.
    Thank you for your help. I tried it following your guide and found it.
> Do I recommend doing this? In general I suggest rather using mtd because it 
> adds other capabilities. There are always some reasons in embedded 
> development why you want to do things differently.
Because I plain to use YAFFS Direct Bootloader, so I must write 4 functions. and,
Following install guide, I patch MTD to kernel 2.4.18 or 2.4.21, both of those cannot
compile success and I must modify some code. So I think MTD is not stable for use.

Best Regards,
Russell Greece.