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I have a Raspberry Pi 400 and am unable to get my Pi to wake when I short GPIO pins 5 and 6. I tried installing the latest version of the bootloader using raspi-config and checked my eeprom file to see that WAKE_ON_GPIO is set to 2 as the docs say that "Pi 400 has a dedicated power button which operates even if the processor is switched off. This behaviour is enabled by default, however, WAKE_ON_GPIO=2 may be set to use an external GPIO power button instead of the dedicated power button."

I have tried powering up by shorting GPIO pins 5 and 6 after shutting down the pi with "sudo shutdown -H now" with no luck.

I have also tried powering up by shorting GPIO pins 5 and 6 after shutting down by editing /boot/config.txt, putting in "dtoverlay=gpio-shutdown,gpio_pin=3" and then shorting GPIO pins 5 and 6.

Has anybody successfully got their Raspberry Pi 400 to start up using the WAKE_ON_GPIO functionality (shorting GPIO pins 5 and 6)?

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2 Answers 2

Reset to default
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This "feature" does not work on the Pi400 because it has additional circuitry to turn power off which completely disables the SOC.

Update: A 2020-11-24 change "If a button on GPIO3 really is requried(sic) then it can be re-enabled by setting WAKE_ON_GPIO=2 but that will consume more power."
NOTE It is unclear why anyone would want to do this.

The same applies on the Pi4 if you disable power on shutdown using POWER_OFF_ON_HALT=1

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  • I can see how that might be the case, but the documentation at Bootloader Configuration says "Pi 400 has a dedicated power button which operates even if the processor is switched off. This behaviour is enabled by default, however, WAKE_ON_GPIO=2 may be set to use an external GPIO power button instead of the dedicated power button." which seems to suggest that this feature works on the Pi400. Do you definitively know otherwise?
    – Bryan
    Jun 2, 2021 at 17:06
  • @Bryan I don't have a Pi400 and this was not in the documentation when I last read it. The original boot code is a Video Core service which requires the SOC to be powered which was the case on shutdown even though the CPU is halted. The Foundation is always changing code but I still don't see how this would be done.
    – Milliways
    Jun 2, 2021 at 22:42
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I guess something has been badly designed on the PI 400 since it appears no-one has been successful in waking it up with GPIO pins. A shame that it's not possible to connect an external button.

The only way I found for starting PI-400, without the use of the button "F10", is to turn off the power and then turn it back on.

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