Next-Gen iPhone Mentioned In 2.2.1 Firmware; Prototypes Already In Wild?

The latest iPhone firmware update, version 2.2.1, contains references to a hitherto unknown iPhone model number, which has led many to suspect that Apple is planning a significant hardware revision.  The new code – "iPhone2,1" – differs from the first and second generation handsets, which were known respectively as "iPhone1,1" and "iPhone1,2"; it can be found in the USBDeviceConfiguration.plist in an unencrypted firmware.

Although it seems obvious that Apple would be working on a replacement to the current iPhone 3G, what's interesting is that prototypes appear to already be in use.  Developers have noticed the "iPhone2,1" reference showing up in advert serving reports (see gallery below), suggesting that Apple engineers are testing the new hardware.

What's unclear is how exactly the hardware for this next-generation device differs from the current iPhone 3G.  An early assumption is that it could include multicore CPU and GPU technology acquired when Apple bought Imagination Technologies. 

[Thanks Simon!]