Thanks xyz321, I'm running CFW 2.12.
 
diag diagmode
reboot
 
 
humax# fdisk -lu /dev/sda
 
Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
 
   Device Boot      Start         End      Blocks  Id System
/dev/sda1               2     2104514     1052256+ 83 Linux
/dev/sda2         2104515  1932539174   965217330  83 Linux
/dev/sda3      1932539175  1953520064    10490445  83 Linux
humax#
 
humax# sbin/tune2fs -l /dev/sda2
tune2fs 1.41.14 (22-Dec-2010)
Filesystem volume name:   <none>
Last mounted on:          <not available>
Filesystem UUID:          da76a1ce-9113-4c4d-837e-e20ffd9d114d
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype n  eeds_recovery sparse_super large_file
Filesystem flags:         signed_directory_hash
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              60334080
Block count:              241304332
Reserved block count:     12065216
Free blocks:              46808758
Free inodes:              60327922
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      966
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8192
Inode blocks per group:   512
Filesystem created:       Sat Jan  1 00:00:17 2000
Last mount time:          Sun Nov 18 14:14:43 2012
Last write time:          Sun Nov 18 14:14:43 2012
Mount count:              5
Maximum mount count:      37
Last checked:             Sat Nov 17 19:13:16 2012
Check interval:           15552000 (6 months)
Next check after:         Thu May 16 20:13:16 2013
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               256
Journal inode:            8
Default directory hash:   tea
Directory Hash Seed:      e2cdd3e7-35cb-4061-8fa9-09678d723167
Journal backup:           inode blocks
humax#
 
1) Please check that I am using the right numbers :
 
Problem LBA = 
530423802
'fdisk' Start address for sda2 = 
2104515
 
The filesystem block of the bad sector should be :
 
fsblock = (int)( (<problem LBA> - <partition start LBA>) * <sector size> / <fs block size>
 
fsblock = ((530423802 - 2104515) * 512) / 4096
 
I first tried it using calculator, assuming the numbers are decimal and I got 66039910, converted to hex gives me 0x3EFB066, but when I tried it using dc command I get less 
 
humax#
 dc
16 o 530423802 2104512 - 512 * 4096
 
/ p
3efb067
 
2) So is my block is 
66039911 dec ? (i.e. 0x3efb067)
 
I tried the debugfs but couldn't get it to return the inode number ?
 
humax# 
debugfs
debugfs 1.41.14 (22-Dec-2010)
debugfs:  open /dev/sda2
testb 66039911
icheck 66039911