Found this:
Reset to Default Settings:
The GPS module can be reset to its original default settings by pulling BOOT_INT high(3.3V) during a power cycle (Antaris Manual, p. 122). It may be required after a wrong firmware upgrade or a bad configuration change.
......
http://ebookbrowsee.net/antaris4-modules-sim-gps-g4-ms4-05007-pdf-d401683513