I've got two EVBs and both are now dead, unable to respond to either the JLink via JTAG or the OpenSDA on board. JLink reports that it cannot connect (and reads an invalid implementer code of 0x00 from CPUID). It looks like on both boards the chip is dead. The P&E debugger reports that the chip is secure and it should do a full erase, but I don't think that's really true. In any case, it doesn't bring the chip back.
I have been writing code to turn on SOSC and use the external crystal on the EVB. Could this have killed the chip in some way? I checked the schematics to see that it was an 8MHz crystal with the 1MOhm feedback resistor and should be driven with high gain. Is it possible that something is wrong here?