[U-Boot] About uClinux auto start ?

The env set as below:

bootcmd=run flashboot flashboot=sf probe 1; sf read 0x1000000 0x30000 0x320000; bootm 0x1000000

After enter the uboot console, uClinux can be started by command "boot"; but after power on (reset) the board, the error info is: * * *SF: Detected M25P32 with page size 256, total 4 MiB* *4096 KiB M25P32 at 0:1 is now current device* *Wrong Image Format for bootm command* *ERROR: can't get kernel image!*

So how to setup to make sure uClinux could be auto started after power on ?