I'm afraid I don't understand what you mean by:
[quote user="Michi Yama"]On current customer's connection between NAND to GPMC, address bit "0" is Low. So NAND access is only 16bit. But customer says NAND access looks like 8 bit access even though 16bit access mode hardware setting.[/quote]
AM3517 has no hardware setting for NAND bus width.