Does the scatter loading file mechanism have some method of adding a checksum to a rom region? And, most of all, if this exist: Can the checksum be reproduced by the target? Doing this manually for each release firmware is possible, but not preferred.
There is the ElfDwt tool, but I cannot find the method used to create the checksum. And this only seems to apply to the vector table to have NXP bootloaders accept the code.
I'd like to continuously check the startup file .o integrity and a one time boot .ANY ROM check. This since the product is placed in some hotter environments, which can cause issues.
If you use a hex file as output, then you link twice, convert to hex and then modify the hex file to contain an extra line with the address of the checksum and the value of the checksum.
The hex file supports multiple flash address ranges, in case you have a processor where the flash doesn't represent a single linear block. And it also support holes, so if the binary only fills half the flash, then the hex file can skip over unused space in case you want to use the last 16 bytes for a checksum.
I didn't know that hex files supported multiple ranges. I'll look into that. Being able to reserve a CRC area and have my own python script create crc and store it in that region might be an possibility.