Want to pretend your iPhone 4S is 4G? Just install iOS 5.1

If you’ve been dreaming of having a 4G iPhone, your wish can be granted today… sort of.

Coinciding with the launch of its new iPad, Apple has also released iOS 5.1 for existing devices. As expected, it adds Japanese language support for Siri, but to our surprise it also made a pretty significant change to the iPhone 4S status bar: instead of “3G” being listed next to AT&T, it now says “4G.”

The iPhone 4S supports HSPA+ networks up to 16 megabits per second, which is just enough to count as 4G in AT&T’s book as well as that of the FCC (even though HSPA+ is not technically a fourth-generation technology like LTE). When the iPhone 4S first launched in October, 2011, Apple revealed that it was working together with AT&T to make the 4G indicator show up.

Notably, the 4G designation will only show up on iPhone 4S units running on AT&T’s network. Verizon and Sprint both use CDMA technology for their 3G networks, and CDMA is significantly slower than HSPA+’s 16Mbps. Compared to the iPhone 4, which didn’t support the faster HSPA+ speeds, my iPhone 4S has performed much better in New York City, with download speeds between 2 and 5 megabits per second. That’s about twice as fast as what I saw on the iPhone 4.

Other new features in iOS 5.1 include a camera shortcut on the lock screen (also previously rumored), as well as the ability to delete photos from the iCloud Photo Stream, which is indispensable if you ever take pictures of your, um, private parts, since iOS can be set to automatically upload any photos you take to iCloud. (According to Cult of Mac writer Charlie Sorrel, the OS update also improves the quality of photos taken by the iPad 2, making them less grainy.)

To download the iOS 5.1 update directly to your iOS device, go to Settings -> General -> Software Update and tap “Download and Install” to begin the download. Tap Learn More to see list of new features included in the update. A pop-up will recommend that you connect to a power source while downloading, but it’s not necessary. The update is 177MB.

Apple also released iTunes 10.6 today, which includes support for 1080p video downloads from the iTunes store.

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