what did error 53 mean for this iphone?
Some hardware integrity checks would trigger an unrecoverable loop into "Recovery Mode" if iOS is updated or restored, with attempts to restore the device via iTunes software resulting in an "error 53" message
IPhone 6
It was reported these same hardware integrity checks would trigger an unrecoverable loop into "Recovery Mode" if iOS is updated or restored, with attempts to restore the device via iTunes software resulting in an "error 53" message. 
how many mp is the iphone 6 front camera UNANSWERABLE when did this phone first come out in the market? September 19, 2014 which company does this iphone belong to? Apple Inc. when was this company founded? April 1976 and who founded it? Steve Jobs, Steve Wozniak and Ronald Wayne how is apple related to macintosh? Apple launched the Macintosh, the first personal computer to be sold without a programming language can you tell me a few products that apple produces? iPhone smartphone, the iPad tablet computer, the Mac personal computer, the iPod portable media player, the Apple Watch smartwatch who is the design of the logo attributed to? Rob Janoff does this company also have a charitable trust? UNANSWERABLE what kind of chipsets does the iphone 6 have? Apple A8 system-on-chip, and an M8 motion co-processor does this version of iphone also have good connectivity? Yes. The expanded LTE connectivity is improved to LTE Advanced, with support for over 20 LTE bands did the iphone have any hardware issues? Yes. Concerns surrounding their rigidity (which led to incidents surrounding chassis bending, as well as degradation or outright loss of touchscreen functionality)
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IPhone 6 [SEP] "Error 53"
Beyond the explanation that this is related to hardware integrity errors regarding Touch ID components, Apple provided no official explanation of what specifically triggers error 53 or how it can be fixed without replacing the entire device. On February 18, 2016, Apple released an iOS 9.2.1 patch through iTunes which addresses this issue and admitted that error 53 was actually related to a diagnostic check for inspecting the Touch ID hardware before an iPhone is shipped from its factories.