Auto shutdown and start of Raspberry Pi (remote application) using powerboot 1000c - need help debugging the circuit
The circuit you designed works as specified. The issue is in you spec:


  Case 3: V_usb == OFF and LBO == HIGH:
  Rpi is powered by the battery.


This requirement doesn't do anything to prevent the boot-shutdown-boot loop you're seeing. You could avoid this behavior by specifying, for example:


  Case 3: V_usb == OFF and LBO == HIGH:
  If Rpi is running, keep it powered by the battery. Otherwise, don't start it.


This change makes it obvious that your system either needs to keep track of the state, or use an additional signal (RPI_RUN) which your Rpi should pull to HIGH when running. Those possibilities can be illustrated as follows:







simulate this circuit &ndash; Schematic created using CircuitLab