Size: 9735 x 8082 um
Nintendo Co., Ltd. (C) Silicon Graphics, Inc. (m) 1995 All Rights Reserved RCP R???0AAA (probably Rev2.0 as HW2 was retail silicon)
There was a mishap during depackaging which created an invisible microfracture. This expanded during ultrasonic cleaning to eventually split the die in two. Additionally, the (remaining?) passivisation does not protect the chip very well as it was not subject to rough treatment yet has numerous scratches. It is unclear if it had another protective layer that was dissolved by the acid bath.
Top metal @ Mit5x: http://siliconpr0n.org/map/nintendo/rcp-nus/mz_cracked_mit5x/
See wiki for details about this chip: http://en.wikipedia.org/wiki/RCP_%28chip%29