problem about detecting FlashROM

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Dear Sir
	I am trying to boot Linux kernel 2.4.16 on FlashROM
	My environment is 
	board : TOSHIBA TX4927 with FlashROM
 	kernel : linux kernel 2.4.16 with NFSroot ( I wonder whether this
                 root filesystem will affect somethings )
	
	I have builded the Linux kernel with MTD/JIFFS/CFI supported ,
        according to mtd-jffs-HOWTO.txt
	
        But when I type the "modprobe -a physmap" command , it displays
        that " modprobe: Can't locate module physmap "

	Any help would be appreciated.
	Thank you