Distributing Dyn C app/modifying bin with hex editor

Hello !
I have a common problem:
Dyn C app using Ethernet has to be installled to say 10-100 different boards on customer site. Each must have an unique IP address. IP is maintained using IE browser and stored on the flash in the Rabbit board. However initiallly when the bin is downloaded via USB cable the board must have unique IP to connect to.
Now I distribute the app as a source file that is modified compiled and loaded for each board.
I could use the RF field utility to just download the bin, but how to set the IP ? I have tried to use hex editor to modify the bin-file,
but R-utility complains that firmware is not valid, because Dyn C compiler calculates some checksum that is written to the beginning of the bin-file.
Is modifyin bin possible or would there be any better solution ?
I could use DHCP, but the IP can change, and I cannot identify the 10-100 different boards anymore.


Can you explain properly , what is your application and what do you want to do?

If you say what exactly you want to do i will give proper solution.


The app is door control application, each board is associated with door. Each door (board IP) should have unique parameters
(which RF tags are allowed to open the door, for example. RF reader is connected to the serial port). Those parameters are sent to the Rabbit via http, so I need unique IP for every Rabbit board. The problem is how set IP:s initially