I would bet the Checksum would have a file creation date the same as the navboot file

Only a few files do
GSW_tools
lng_rel.tbl
loader.ini
lowboot
sw_rel_tbl

Now lowboot was the last file created and logically would contain the checksum.

Cruzing thru the lowboot file dec location 413417 shows the Error File %s Size %u does not match chain size of %d x %d bytes

I searched for %d and found the following at dec location 395201

Check CRC Valid modules in bootfile %d size 0x%x -> 0x%x

My guess is that you smart guys can modify the lowboot file to either remove the checksum or modifiy as needed

Also note that I have found CheckCRC=%d