Вроде бы у srec_cat есть ключик "игнорировать контрольную сумму", не? http://srecord.sourceforge.net/man/man1/srec_input.html
Ignore Checksums
The −IGnore-Checksums option may be used to disable checksum validation of input files, for those formats which have checksums at all. Note that the checksum values are still read in and parsed (so it is still an error if they are missing) but their values are not checked. Used after an input file name, the option affects that file alone; used anywhere else on the command line, it applies to all following files.