Since upgrading the firmware to the latest version on my CRS125-24G, the wireless master interface is gone from a possible choice. Is there any way I can know for use if it is really dead ? Should I attempt to perform a factory reset ?

F.

If you are unsure what is going on, a re-install, factory reset or even a netinstall is always a good thing to try. There have been several reports of upgrades not going correctly and losing the wireless drivers somehow. A re-install will mostly fix that.