[U-Boot] Problem of porting uClinux

I am trying to port uClinux2.4 to my board [S3C44B0],but got a problem whitch I have no idea.

imagerom.bin was downloaded to 0xc100000 [RAM] and kenel can be run successfully by using command go 0xc100000.

Then I use mkimage -A arm -O linux -C gzip -a 0xc008000 -e 0xc008040 -d image.rom.gz uImage

kermit showed : (when I reset board after downloaded uImage to 0x20000 ) ... ... Verifying Checksum .....ok Uncompressing Kenel Image ...Ok ##Loading Ramdisk Image at 000f0000.... Bad Magic Number

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