The flash memory bug of TLC performance versus MLC leads Apple to fix the memory IC controller and move from MLC to TLC NAND. It takes about a year to implement such changes. In the meantime, Apple looks to Samsung to provide MLC NAND (see the article below).
This is just another example of the limitations that the consolidation of semiconductor fabrication companies cause on their customers such as Apple. More about semiconductor industry consolidation from March 2012 Moore's Law Slowwwing and from February 2013 Semiconductor Moore's Law Running out of Money.
Insightful, timely, and accurate semiconductor consulting.Semiconductor information and news at - http://www.maltiel-consulting.com/