RPi 4 4GB, Power Management & UPS HAT, Official RPi 7" LCD Screen, no screen power up, image

[shawnj007]

Solved this problem with some external hardware.

Immediate power up with external power, safe shutdown when removed

So, no real fix from sixfab, so I came up with something that does the trick. My solution is to simulate a button press when power comes on with hardware using a 555 timer IC. This works for me, it may work for you, but use it at your own risk. The circuit operates by sensing voltage on the power source and uses a mosfet to simulate a quick press on the button. Since the ‘short press’ has no effect when the system is already on, power can be applied/removed in cases where the normal saf…