The problem was the phones battery couldn't deliver enough current to run the cpu at full power, even though it had charge remaining to run the phone for some p

The problem was the phones battery couldn't deliver enough current to run the cpu at full power, even though it had charge remaining to run the phone for some period of time in a lower power mode. Without power management, when a high demand task came alone and the CPU tried to draw more power, the phone would crash or shut-down. The firmware update capped performance not to extend the run-time when the batteries were low, but to allow the phone to run reliably when the batteries were worn.