Raspberry Pi 5 Power Button Not Working in Pimoroni NVMe Case: The J2 Connector Fix

ByPriya Nair

The fix, upfront

The external power button on the Pimoroni NVMe Base Case (PIM771) only works if the cable from that button is connected to the J2 header on the Raspberry Pi 5 board. The J2 header is a pair of small solder pads next to the Pi’s onboard tactile button, and they are easy to miss — or simply forget to wire up — during assembly. That is the first thing to check.

How the Pi 5 power button system works

The Raspberry Pi 5 was the first Pi to ship with a proper hardware power button on the board itself. Press it briefly and the Pi starts a clean software shutdown. If the board is already off but still plugged into power, pressing it again boots the system back up — no need to unplug and replug the USB-C cable.

Crucially, the button connects to the PMIC (power management IC), not to a GPIO pin. That means it works even when the operating system isn’t running, and it does not need a device tree overlay or any entry in config.txt to function. No software configuration required.

Behaviour varies by OS mode. Under Raspberry Pi OS with Desktop, a brief press opens a shutdown confirmation dialog, and pressing the button a second time confirms. Under Raspberry Pi OS Lite — the base for Home Assistant OS — a single short press triggers shutdown directly, no dialog.

What J2 is and why it matters here

The J2 header is a two-pin pad on the Pi 5 board, sitting right beside the onboard tactile button. Electrically, it is identical to that button. Bridge the two pads with a normally-open momentary switch and you get the same power-on, shutdown, and wake behaviour as pressing the built-in button directly.

That is exactly how the PIM771 case’s external button is designed to work. The case ships with a small cable: one end connects to the button embedded in the case shell; the other plugs onto the J2 pads on the Pi 5 board. If that cable isn’t connected — or isn’t fully seated — the case button does nothing. The onboard button will still work, but it’s buried inside the assembled case and impossible to reach.

J2 pads don’t have a header pin pre-soldered on the stock board. The connector can look seated when it isn’t quite making contact. Press it firmly down and verify both wires are touching the correct pads before closing the case up.

Assembly checklist for the PIM771

  • Locate J2 on the Pi 5 — two small gold pads near the corner of the board, right beside the onboard tactile button.
  • Route the button cable so it won’t be kinked or pinched once the lid closes.
  • Press the cable connector firmly onto J2. For a normally-open momentary switch, polarity typically doesn’t matter, but check Pimoroni’s assembly guide for your specific cable revision to be sure.
  • Test the button while the case is still open before tightening the screws down.

If J2 is connected but the button still doesn’t respond

First, test the onboard tactile button directly. If that also fails to trigger a shutdown, the problem is probably not the cable.

Check /boot/firmware/config.txt (or /boot/config.txt on older images) for any overlay that might conflict with PMIC power management. Nothing needs to be added for J2 to function — it operates at the hardware level — but some third-party power management scripts can interfere.

Running sudo rpi-eeprom-update and applying any available firmware update is worth doing. A handful of early Pi 5 firmware revisions had rough edges around power button behaviour that were resolved in later releases.

One note if you’re reading this after trying a different approach: wiring a separate GPIO pin for shutdown is a distinct setup and does require an overlay, such as:

dtoverlay=gpio-shutdown,gpio_pin=3,active_low=1,gpio_pull=up

But for the PIM771’s built-in button connecting to J2, no overlay is needed — and adding one won’t help if the physical cable connection is the actual issue.

Notes for Home Assistant

Home Assistant OS runs headless and doesn’t show a desktop shutdown dialog. A short press sends a shutdown signal straight to the system. The power LED dims once the shutdown completes. If the LED stays solid after pressing the button, the signal is not reaching the PMIC — which leads straight back to the J2 cable.

If you’re on an older HAOS release, updating before going deeper into hardware diagnostics is a reasonable step. Power management support on Pi 5 hardware improved across later HAOS versions. You can update from Settings > System > Updates in the Home Assistant interface, or via the HA CLI with ha os update.

Sources


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