I have a image file named "xyz.img". I need to change some of the content in the image file (say one or two bytes). I hexdump it by using the command
hexdump -x xyz.img > hex1
Now when i am opening the "hex1" using vi, it is showing like this:
0000000 ffff ffff ffff ffff ffff ffff ffff ffff
*
0000020 ffff ffff 00ff ffff ffff ffff ffff ffff
0000030 ffff ffff ffff ffff ffff ffff ffff ffff
*
0001000 0568 28ca b438 0420 f746 1080 ffff ffff
0001010 e469 8108 026b a01f 8086 10d3 ffff 9c5a
0001020 0000 2001 7e94 ffff 1000 0048 0000 2704
0001030 6cc9 3150 073e 460b 2d84 0140 f000 0706
0001040 6000 7100 1408 ffff 4d01 92ec fc5c f083
0001050 0028 0233 0050 7d1f 1961 0453 00a0 ffff
0001060 0100 4000 1315 4003 ffff ffff ffff ffff
0001070 ffff ffff ffff ff..................................
.......................................................................
..........................................................
I couldn't post the whole as it is too large. Now I need to replace one or two bytes. Ultimately my CRC Byte will also get change.
where this CRC is located and how could I modify the CRC as per as the replaced bytes?