我使用at91sam9m10g45ek board.i想从Nandflash启动 . linux 3.12无法在从nandflash启动时挂载jffs2 . 我的u-boot参数：
bootargs = console = ttyS0,115200 earlyprintk mtdparts=atmel_nand:256k(bootstrap)ro,512k(uboot)ro,256k(env),256k(env_redundant),256k(spare),512k(dtb),6M(kernel)ro,-(rootfs) root=/dev/mtdblock7 rw rootfstype=jffs2
错误：
VFS: Cannot open root device "mtdblock7" or unknown-block(31,7): error -19 Please append a correct "root=" boot option;
如何解决这个问题??请帮我解决这个问题 . 提前致谢 .