The application software and configuration files have and adjacent .inf file with version info and CRC Checksum.

That Checksum is based on a standard crc16 algorithm but with a non standard polynomial generator.

In most cases, in order for the system to accept a modified file the checksum must be correct.
Some tests were made with the BootScreen.bmp File (Splash screen when the system boots)

It was found by trial & error that the checksum consists of 2 parts:

- The last 4 chars (ASCII value of a 16 bits word) are a CRC16 of the main file using the internal algorithm.
- The first 4 chars (ASCII value of a 16 bits word) are a CRC16 of the whole .inf file, excluding the first 4 bytes

RT4Inf, a tool to calculate .inf files and crc is available at the page bottom, in the files section. (click on the files button).

example .inf file:



2424 - CRC for the Marelli.bmp file
9753 - CRC for the Marelli.bmp.inf, without the first 4 bytes.

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