In message 200505111408.AA28377416@RCS-9000.COM you wrote:
I have no ethernet device on my board,so I can only load linux img file via serial port using "loadb" command. But when I downloaded the img successfully and tried to boot the linux , the program stopped as follows:
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Kernel command line:
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VFS: Unable to mount root fs via NFS, trying floppy. VFS: Cannot open root device "" or 02:00 Please append a correct "root=" boot option Kernel panic: VFS: Unable to mount root fs on 02:00
Well, you don't pass any boot arguments to the linux kernel (like where to find a root filesystem), so your kernel quite naturally complains that he cannot find the root file system.
Looks perfectly normal to me.
Best regards,
Wolfgang Denk