Apparently the MP2667 cannot power (through VSYS) a CPU that has a GPIO connected to the MP2667 INT pin. The hope was to allow the powered CPU (by VBATT, with Vin at zero) put itself into shipping mode by driving INT low for over eight seconds. VSYS does indeed go low and the CPU power drops, but the INT pin is forced low through the CPU’s ESD diodes. And that reconnects the battery and powers up VSYS and the CPU. It appears that this simple circuitry, charger and battery powering a CPU, isn’t so simple. Some sort of isolator/level shifter is necessary to disconnect the CPU GPIO from INT to prevent the above scenario. Am I missing something?