Although the new CECH-2100A SKU hasn’t been formally announced by Sony, there’s sayings that Sony updated the Playstation’s Hardware by changing the RSX for a cheaper one, which uses 15% less power, and is less likely to be affected by the YLOD.
According to Engadget, the new RSX is 40nm compared to the older 65nm, and it uses two 128Mb XDR RAM chips instead of the four 64Mb version.
Perhaps Sony planned to announce this at E3? i doubt it, but expect an official word on this very soon.