Based on information provided in another post, it appears that PowerBlock is not compatible with Pi 400.

Info from other post: "The PowerBlock provides power to the GPIO pins 2 and 4 switched via a power switch IC.
The Pi 400, though, cannot be powered via it's GPIO pins, see https://www.hackster.io/news/raspberry-pi-400-design-change-puts-an-end-to-battery-power-gpio-add-on-boards-770826a23ed9.".

Thanks for your response - very helpful.

I'm a stubborn SOB...do you think it would be possible to connect this (https://www.digikey.ca/en/products/detail/sparkfun-electronics/BOB-15100/9770720) to the PowerBlock to send power from the PowerBlock via USB-C to the Pi 400? I could then connect the relevant pins from PowerBlock to the Pi 400 (pins 5 and 6, I assume) and pins 2 and 4 to the BOB-15100 (USB-C adapter I linked to).

Alternatively, I may just have to purchase a regular Pi 4...

I want the external power button as I'm planning to put the Pi within a custom-built arcade. I bought the Pi 400 thinking this would be easier (with the built-in keyboard)....but I'm beginning to see that maybe that's not the case.

@petrockblog Excellent, thank you for the information!

@tsarevfs Hi, unfortunately, the PowerBlock does not provide this capability because it does not loop through the data lines of the USB connector.

ugh!! i must have moved it while reformatting my sd card! this was the problem. thanks for the help!

Hi! I am sorry to hear that! We tested the PowerBlock with quite a few extension boards and that should not happen at all.
Please contact me via email or webform (https://www.petrockblock.com/contact/) so that we can arrange a replacement.

Glad to hear that :-)

Thanks for the kudos!

There seemed to be some sort of network problem. Does the problem still exist for you?

You could try and not connect the PowerBlock via the 2x6 pin header but connect the PowerBlock with jumper wires. You could then change the status and shutdown pins in the configuration accordingly.

Glad to hear that :-)

@BuZz Thanks a lot Jools! :-)

It is fixed now. Please see https://retropie.org.uk/forum/topic/23328/powerblock-driver-quick-installation-fails/5.

Glad to hear that!

@petrockblog Still interested. Sent you an e-mail. Thanks.

Glad to hear that!

I have updated the instant scripts such that the libc6 and libc6-dev packages are also automatically installed.

For future note: I removed the dependency to WiringPi now. Please see also https://retropie.org.uk/forum/topic/23328/powerblock-driver-quick-installation-fails/5.

Good to hear all is working well!

I still need to buy a Pi 4 so it will take some time for testing it out..

Thanks for the support!

So, I have mounted the PowerBlock and I have tested it for some days. It works almost as expected, spordically it shows unexpected behaviour. I will create a separate thread explaining my observations.

Anyway, thanks for supplying me with a replacement device.