I am migrating from the 4Mb Am29LV040B to the 8Mb S29AL008J. How do I treat "A18" pin on S29AL008J if Byte mode is used?
It depends on which model of the S29AL008J you use. If you use model 01(top-boot), you should connect A18 to logic low; If you use model 02 (bottom-boot), you should connect A18 to logic high. Either connection will make the S29AL008J sector architecture look identical to the Am29LV040B.