root@OpenWrt:~# 
root@OpenWrt:~# 
root@OpenWrt:~# flash_erase /dev/mtd12 0 0
Erasing 128 Kibyte @ b6a0000 -- 59 % complete flash_erase: Skipping bad block at 0b6c0000
Erasing 128 Kibyte @ 131e0000 -- 100 % complete 
root@OpenWrt:~# 
root@OpenWrt:~# 
root@OpenWrt:~# 
root@OpenWrt:~# nanddump /dev/mtd12 > /dev/null
ECC failed: 1124
ECC corrected: 0
Number of bad blocks: 1
Number of bbt blocks: 0
Block size 131072, page size 2048, OOB size 64
Dumping data starting at 0x00000000 and ending at 0x13200000...
root@OpenWrt:~# 
root@OpenWrt:~# 
root@OpenWrt:~# 
root@OpenWrt:~# nanddump /dev/mtd12 > /dev/null
ECC failed: 1124
ECC corrected: 0
Number of bad blocks: 1
Number of bbt blocks: 0
Block size 131072, page size 2048, OOB size 64
Dumping data starting at 0x00000000 and ending at 0x13200000...
root@OpenWrt:~# 
root@OpenWrt:~# 
root@OpenWrt:~# 
root@OpenWrt:~# ubiformat -s 2048 -e 11 /dev/mtd12
ubiformat: mtd12 (nand), size 320864256 bytes (306.0 MiB), 2448 eraseblocks of 131072 bytes (128.0 KiB), min. I/O size 2048 bytes
libscan: scanning eraseblock 2447 -- 100 % complete  
ubiformat: 2447 eraseblocks are supposedly empty
ubiformat: 1 bad eraseblocks found, numbers: 1462
ubiformat: use erase counter 11 for all eraseblocks
ubiformat: formatting eraseblock 2447 -- 100 % complete  
root@OpenWrt:~# 
root@OpenWrt:~# 
root@OpenWrt:~# 
root@OpenWrt:~# nanddump /dev/mtd12 > /dev/null
ECC failed: 1124
ECC corrected: 0
Number of bad blocks: 1
Number of bbt blocks: 0
Block size 131072, page size 2048, OOB size 64
Dumping data starting at 0x00000000 and ending at 0x13200000...
ECC: 5 uncorrectable bitflip(s) at offset 0x00b80000
ECC: 5 uncorrectable bitflip(s) at offset 0x02700000
ECC: 1 corrected bitflip(s) at offset 0x02720000
ECC: 2 uncorrectable bitflip(s) at offset 0x04300000
ECC: 4 uncorrectable bitflip(s) at offset 0x04320000
ECC: 5 uncorrectable bitflip(s) at offset 0x05f20000
ECC: 4 uncorrectable bitflip(s) at offset 0x07b40000
ECC: 4 uncorrectable bitflip(s) at offset 0x09740000
ECC: 4 uncorrectable bitflip(s) at offset 0x0b3c0000
ECC: 5 uncorrectable bitflip(s) at offset 0x0b3e0000
ECC: 5 uncorrectable bitflip(s) at offset 0x0d060000
ECC: 5 uncorrectable bitflip(s) at offset 0x0ec80000
ECC: 4 uncorrectable bitflip(s) at offset 0x10980000
ECC: 5 uncorrectable bitflip(s) at offset 0x109a0000
ECC: 5 uncorrectable bitflip(s) at offset 0x12580000
ECC: 1 corrected bitflip(s) at offset 0x125a0000
root@OpenWrt:~# 
root@OpenWrt:~# 
root@OpenWrt:~# 
root@OpenWrt:~# nanddump /dev/mtd12 > /dev/null
ECC failed: 1186
ECC corrected: 2
Number of bad blocks: 1
Number of bbt blocks: 0
Block size 131072, page size 2048, OOB size 64
Dumping data starting at 0x00000000 and ending at 0x13200000...
ECC: 5 uncorrectable bitflip(s) at offset 0x00b80000
ECC: 5 uncorrectable bitflip(s) at offset 0x02700000
ECC: 1 corrected bitflip(s) at offset 0x02720000
ECC: 2 uncorrectable bitflip(s) at offset 0x04300000
ECC: 4 uncorrectable bitflip(s) at offset 0x04320000
ECC: 5 uncorrectable bitflip(s) at offset 0x05f20000
ECC: 4 uncorrectable bitflip(s) at offset 0x07b40000
ECC: 4 uncorrectable bitflip(s) at offset 0x09740000
ECC: 4 uncorrectable bitflip(s) at offset 0x0b3c0000
ECC: 5 uncorrectable bitflip(s) at offset 0x0b3e0000
ECC: 5 uncorrectable bitflip(s) at offset 0x0d060000
ECC: 5 uncorrectable bitflip(s) at offset 0x0ec80000
ECC: 4 uncorrectable bitflip(s) at offset 0x10980000
ECC: 5 uncorrectable bitflip(s) at offset 0x109a0000
ECC: 5 uncorrectable bitflip(s) at offset 0x12580000
ECC: 1 corrected bitflip(s) at offset 0x125a0000
root@OpenWrt:~# 
root@OpenWrt:~#