Remember Monday’s post about the problems some of China Mobile’s 15 million unofficial iPhone users were having on the carrier’s network? In that post, we quoted China Mobile as saying that an upcoming update would fix the problems.

Sure enough, that fix came yesterday in the form of iOS 5.1. Our buddies at M.I.C. Gadget confirm that the latest iOS update resolved the issue, which manifested itself as an inability to make calls even when the signal indicator was showing full strength.

The issue kept many iPhone 4S owners from activating their phones when a China Mobile SIM was inserted. Once iOS 5.1 is installed on the iPhone, the carrier is listed as “China Mobile 12.0.”

Of course, the “4G” iPhone 4S still runs on 2G EDGE on the China Mobile network. As M.I.C. Gadget points out, it was important for Apple to fix the issue even though China Mobile isn’t an official carrier. Why? China Mobile is China’s largest carrier, with 75 percent market share and about 650 million customers. Even “unofficial” iPhone users on the China Mobile network means more sales for Apple.

M.I.C. Gadget ends its post wondering “when on earth will China Mobile adapt the international 3G/4G standard to ease the difficulties Apple is facing on making a 4G LTE iPhone for China Mobile?” For a potential market of 650 million customers, you think that Apple would consider making an iPhone specifically for China Mobile’s network.

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