In case of a software or calibrationfile update you should use update which can be find in the root-directory of the WFC software. The purpose of update is to modify the file attributes of the files mentioned in the update file. While source-files are shipped read-only, they must be changed to writable in order the update to succeed. So
$ ./update wfc_stage2-038
Will do the job. Note update is called with the basename only! No suffixes should be given. The update script will supply them automatically. Beware the script uses gunzip , chmod , tar and grep . In case one of the programs cannot be found the update will fail. Also if your system does not have gunzip you will have to modify update .