USB口插着U盘从NAND启动错误的问题

启动参数：setenv bootargs 'mem=128M console=ttyAMA0,115200 root=/dev/mtdblock2 rootfstype=yaffs2 mtdparts=hinand:1M(boot),7M(kernel),248M(rootfs)'
插着U盘，从nand启动的时候，会打印以下错误，什么问题？
[code]scsi 2:0:0:0: Direct-Access     TOSHIBA  TransMemory      1.00 PQ: 0 ANSI: 4
sd 2:0:0:0: [sdb] 7574304 512-byte logical blocks: (3.87 GB/3.61 GiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
sdb: sdb1
sd 2:0:0:0: [sdb] Attached SCSI removable disk
map_over_bad_blocks(): no more good blocks!
map_over_bad_blocks(): no more good blocks!
map_over_bad_blocks(): no more good blocks!
map_over_bad_blocks(): no more good blocks!
map_over_bad_blocks(): no more good blocks!
map_over_bad_blocks(): no more good blocks!
map_over_bad_blocks(): no more good blocks!
map_over_bad_blocks(): no more good blocks!
EXT3-fs (sdb1): error: couldn't mount because of unsupported optional features (240)
Disk /dev/sda: 2000GB
/dev/sda is a harddisk
Find Disk /dev/sda
Find Disk /dev/sda1
/dev/sda is parted
/dev/sda is OK
EXT2-fs (sdb1): error: couldn't mount because of unsupported optional features (240)
EXT4-fs (sdb1): warning: maximal mount count reached, running e2fsck is recommended
EXT4-fs (sdb1): mounted filesystem with ordered data mode. Opts: [/code]