Topic created on: September 4, 2008 13:40 CDT by rman .

Followup to my previous post about the cisf images.

Currently in the process of reversing an vxworks (5.5 by the strings) binary (arm processor), and get to the point that I can upload my own firmware.  Trail and error has proved to me that the files have a checksum in them (no surpise) as I cannot change the value of a character without the device rejecting the flash.

After poking around with a hex editor for quite a while I've hit a wall.  A few of the more promising locations havent worked out, and I'd love some advice.

Right not I'm thinking writing up a quick script to iterate through the file setting each 1,2,4 byte combination to x00, running all the common checksum algorithms against it and seeing if I get any matches.

Is this the best method, or are there better/simpler methods that Im overlooking?