Microsoft Tuesday began delivering an update to Windows Phone 8 smartphones that provides unspecified "performance enhancements" that some customers say include an OS fix for random reboots and Wi-Fi enhancements.
A spokeswoman said Tuesday that "Microsoft isn't going into detail into the specific enhancements at this time."
Microsoft is working with carriers and hardware partners to get the update tested, approved and rolled out, she added. "Some customers are starting to receive it now," she said.
Customers on online forums late yesterday reported the delivery of an update called Portico for the Windows Phone 8 HTC 8X that provides fixes for random rebooting problems and adds a Wi-Fi enhancement.
Users last month began reporting random reboots on both HTC 8X and Nokia Lumia 920 smartphones supplied by various carriers around the globe.
Microsoft acknowledged the problem announced on Nov. 27 that a fix for the unexpected reboots was in the works and would be released sometime in December.
The Portico over-the-air update appears to apply so far only to the HTC 8X international version of the smartphone, based on a report and video posted on Windows Phone Central.
HTC could not be reached for comment on the progress on the update for its phones. Microsoft also had not posted an explanation of the update on its update history Web site as of early Tuesday.
Three carriers in the U.S. -- Verizon Wireless, AT&T and T-Mobile USA -- sell the HTC 8X or the lower cost HTC 8S for their networks. Forum users reported that they were not seeing an update delivered for carrier-specific phones, according to users on one user forum.
Very often, carriers want to independently review updates before releasing them to their customers.
None of the carriers responded to requests for comment on the update.
The Wi-Fi enhancement in the update allows a continuous wireless LAN connection that works even when the display is off, according to users and Windows Phone Central.
The video on Windows Phone Central showed the update on the international version of HTC 8X. It took eight minutes to download the over-the-air update to the Windows Phone 8 OS itself.
The following installation of the update took more than 10 minutes, an indication that the update is substantial.
The update took the OS build from 8.0.9905 to 8.0.10211.
Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at @matthamblen, or subscribe to Matt's RSS feed . His e-mail address is email@example.com.