Apple Fixes iPhone 4S Compatibility Issue With China Mobile SIM Cards

The Next Web reports that Apple has fixed the iPhone 4S compatibility issue with China Mobile SIM cards. Due to the issue, China Mobile customers were unable to make calls even though they had a full signal in their area.

The Next Web reports that Apple had acknowledged the issue back in February and has fixed the issue by "modifying how iPhone 4S interacts with the GSM chip".

The issue is believed to have been caused by GSM chips which support the P frequency band (885-915MHZ), but not the E frequency band (880 – 890MHz). This led to many users finding they had full signal in indoor areas, but were unable to make calls.

It looks like Apple has fixed the issue in iPhone 4S units manufactured after February 8th. But those who had purchased iPhone 4S units manufactured before that will have to wait for Apple to release an iOS software update to fix the issue. We're assuming that China Mobile is referring to iOS 5.1 software update that is expected to be released on or around March 9th.

Even though Apple has not partnered with China Mobile yet, it is important for Apple to fix the issue as it is the country's largest mobile carrier with more than 70% of the market share (or more than 650 million subscribers). China Mobile  also announced earlier today that it has more than 15 million (unlocked) iPhone users on their network. They claim that more than 5 million iPhone 4S' were activated by them ever since it was launched back in October.

It's not clear what change Apple has implemented to fix the issue in iPhone 4S units manufactured after February 8th,   as the tweaked version of iOS 5.0.1 released back in mid-December 2011 was the last software update. We'll update this post if we get more information.

Apple is expected to release iOS 5.1, which should include a fix for the issue on or around March 9th.

[via The Next Web]