IPhone 7 lock that prevents individuals from attempting to replace the home button on their own. Users are now required to go to an Apple Store to have repairs done, with "recalibration" of the button being necessary. This is a step further than Apple went with iPhone 5S, 6 and 6S, where only Touch ID functionality would get disabled but the "return-to-home" functionality still worked. Some iPhone 7 devices with the model numbers A1660, A1779 and A1780 suffer from a problem where they show a "No service" message even when cellular reception is available. Apple will repair those devices for free within
IPhone 3GS SGX 535 GPU. It has 256 MB of package on package (PoP) DRAM, twice the amount of the 3G, allowing for increased performance and multi-tasking. Apple claims the iPhone 3GS is 2x faster than its predecessor, showing demonstrations of various apps loading in half the time its predecessor does. As on previous models, all data is stored in flash memory and not in the SIM and it does not offer any options to expand storage. Initially it was only available in 16 and 32 GB though an 8 GB model was later released, with Apple discontinuing the 16 and 32