bcm7581nandflas烧写

#ifconfig eth0 -addr=192.168.3.47 -mask=255.255.255.0 -gw=192.168.3.250 -dns=172.28.0.2
#flash  -forceerase -noheader 192.168.3.45:ubifs-128k-2048-7552b0.img  flash0.rootfs 
#flash -noheader -forceerase 192.168.3.45:vmlinuz-7552b0 flash0.kernel
#boot -z -elf flash0.kernel: 'ubiroot   root=/dev/mtdblock6 mtdparts=brcmnand.0:512k(cfe),512k(nvram),10240k(loader),512k(hwconfig),512k(caverify),4096k(kernel),-(rootfs)'
#setenv -p STARTUP "boot -z -elf flash0.kernel: 'ubiroot root=/dev/mtdblock6 mtdparts=brcmnand.0:512k(cfe),512k(nvram),10240k(loader),512k(hwconfig),512k(caverify),4096k(kernel),49152k(rootfs),42496k(userdata),512k(ipdata),1024k(cadata),5120k(logo),512k(ldflage),5120k(adlogo),-(reserved)'"
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 第一次、二次可以成功挂上文件系统、第三次就会出现问题，挂载报错
究其原因是 nandflash 的烧写快，但是容易在烧写过程中存在坏块。

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.  其原因参考

大致是这样，nandflash 在每次擦除信息之后，可能会清掉原有的reboot信息，导致坏块，而一旦产生坏块，下次擦除时，就跳过该片段
下次，若nandflash未更新坏块区的信息，则烧写会出现ECC错误！！
解决方法，烧写时，每次烧写最好能通过网络更新烧写的文件系统、kernel

PM: CP0 COUNT/COMPARE frequency depends on divisor
UBI: attaching mtd6 to ubi0
UBI: physical eraseblock size:   131072 bytes (128 KiB)
UBI: logical eraseblock size:    126976 bytes
UBI: smallest flash I/O unit:    2048
UBI: VID header offset:          2048 (aligned 2048)
UBI: data offset:                4096
scsi0 : usb-storage 1-1:1.0
UBI: max. sequence number:       5
UBI: attached mtd6 to ubi0
UBI: MTD device name:            "rootfs"
UBI: MTD device size:            48 MiB
UBI: number of good PEBs:        384
UBI: number of bad PEBs:         0
UBI: number of corrupted PEBs:   0
UBI: max. allowed volumes:       128
UBI: wear-leveling threshold:    4096
UBI: number of internal volumes: 1
UBI: number of user volumes:     1
UBI: available PEBs:             0
UBI: total number of reserved PEBs: 384
UBI: number of PEBs reserved for bad PEB handling: 3
UBI: max/mean erase counter: 2/0
UBI: image sequence number:  829917279
UBI: background thread "ubi_bgt0d" started, PID 430
brcmnand brcmnand.0: uncorrectable error at 0x1061e00
brcmnand brcmnand.0: uncorrectable error at 0x1062600
brcmnand brcmnand.0: uncorrectable error at 0x1062e00
brcmnand brcmnand.0: uncorrectable error at 0x1063600
UBI error: ubi_io_read: error -77 (ECC error) while reading 126976 bytes from PEB 3:4096, read 126976 bytes
brcmnand brcmnand.0: uncorrectable error at 0x1081e00
brcmnand brcmnand.0: uncorrectable error at 0x1082600
brcmnand brcmnand.0: uncorrectable error at 0x1082e00
brcmnand brcmnand.0: uncorrectable error at 0x1083600
UBI error: ubi_io_read: error -77 (ECC error) while reading 126976 bytes from PEB 4:4096, read 126976 bytes
brcmnand brcmnand.0: uncorrectable error at 0x1141800
UBI error: ubi_io_read: error -77 (ECC error) while reading 11 bytes from PEB 10:6144, read 11 bytes
VFS: Cannot open root device "ubi0:rootfs" or unknown-block(31,0)
Please append a correct "root=" boot option; here are the available partitions:
1f00             512 mtdblock0  (driver?)
1f01             512 mtdblock1  (driver?)
1f02           10240 mtdblock2  (driver?)
1f03             512 mtdblock3  (driver?)
1f04             512 mtdblock4  (driver?)
1f05            4096 mtdblock5  (driver?)
1f06           49152 mtdblock6  (driver?)
1f07           42496 mtdblock7  (driver?)
1f08             512 mtdblock8  (driver?)
1f09            1024 mtdblock9  (driver?)
1f0a            5120 mtdblock10  (driver?)
1f0b             512 mtdblock11  (driver?)
1f0c           15872 mtdblock12  (driver?)
1f0d           46748 mtdblock13  (driver?)
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(31,0)
Rebooting in 180 seconds..