updated 09:30 pm EDT, Thu September 19, 2013
More glue for battery, A7 processor, camera notably different
The team at iFixit have gotten a hold of a gold iPhone 5s and published a short teardown guide for the unit, revealing very few changes (as expected) from the iPhone 5 apart from a slightly bigger battery, a new processor and a new camera assembly, now revealed to be supplied by Sony. Apple has kept the camera at 8MP but increased the size of the sensor and pixels to be larger, allowing more color and light in.
Small changes include a different method of gluing the battery into place, a different Bluetooth/802.11 combo chip, the streamlining of components so that interconnect cabling is no longer required, and on the gold model the use of small gold screws. The battery is now glued in using two adhesive strips rather than the iPhone 5's small amount of crazed glue, making removal much more difficult but not impossible.
The iFixit team also disassembled the Touch ID fingerprint sensor and noted that it uses small CMOS sensor to digitally image the fingers. The choice may result in future repairs, as CMOS sensors tend to wear out over time (longer than the normal expected three-year lifespan of an iPhone, but eventually). The camera module, made by Sony, hasn't been seen previously and is somewhat different from the 8MP sensor used in the iPhone 5. Apple's software also lets the camera be used to shoot in "square" format alongside the usual offerings in iOS 7, and the video is now capable of 120fps capture, allowing for flawless slow motion if desired.
In addition, iOS 7 brings support for "Hotspot 2.0" features, which include automatic supplying of login credentials to make frequent public or work Wi-Fi network joining seamless. There are also a number of improvements incorporated in the Accessibility section of iOS 7, including support for Made for iPhone hearing aids (for the iPhone 5 and later).
An earlier iExpert.com teardown of both the 5s and 5c noted that the company has added an extra layer of coating to switches, which may aid in preventing internal failures. The iExperts who did the Australian teardown also noted that the batteries are slightly different (the iPhone 5c uses a 5.73Whr battery while the iPhone 5s has a 5.92Whr rating) and that both are stamped "Apple Japan," suggesting a change in suppliers.
The screws used in the iPhone 5s are again the same pentalobe screws used in the iPhone 5, requiring a special tool to remove. Replacement screws in the gold color are not yet available to repair techs.
One note of caution sounded by the iFixit techs to users attempting a home repair is that in addition to several specialized tools, there is a flexible cable connecting the display assembly to the rear chassis, which could be damaged when using a suction cup to separate the two. The cable connects the Touch ID sensor to the main assembly, but can be gently freed with the help of a spudger.