During the iPhone 5 teardown, we referenced the B8164B3PM silkscreen label, which denoted 1GB of Elpida LP DDR2 SDRAM.

The die mark (first image) and die photo (second image) confirm the strong hunch that the A6's 1GB LP DDR2 SDRAM is provided by Elpida.

According to Chipworks, the Elpida EDB8164B3 was also found in the Motorola Droid RAZR Maxx.