Retrofitting the PiDock 400 to Support the Raspberry Pi 500

The PiDock 400 was designed exclusively for the Raspberry Pi 400 However, with the release of the new Raspberry Pi 500 many of us hoped to use the same docking station since the two devices share nearly identical form factors.

Unfortunately, the PiDock 400 doesn’t supply enough power for the RPi 500. When connected, you’ll see multiple warnings such as:

This power supply is not capable of supplying 5A. Power to peripherals will be restricted.

While the RPi 400 only needed a 5V 3A power source, the RPi 500 requires 5V 5A.

To make the PiDock 400 compatible, I retrofitted it by adding a buck converter that steps down the dock’s internal 12V supply to a clean, stable 5V 5A output.

This guide walks you through every step of the process - from disassembly to testing - so you can safely and neatly upgrade your PiDock 400 for full Raspberry Pi 500 compatibility.

Electronics & Components

1. PiDock 400
2. Raspberry Pi 500
3. 12V DC power supply (at least 6A recommended; I used 8A)
4. Buck converter (12V → 5V 5A) with USB-A or USB-C output
5. 2-conductor cable, AWG16 (≈1.5mm²), ~1m length (red & black preferred)
6. Heat shrink tubing (various diameters)
7. Double-sided tape or hot glue (for securing components)

Tools

1. Soldering iron + solder
2. Desoldering pump (optional, for removing connectors)
3. Wire strippers and cutters
4. Continuity tester or multimeter
5. Plastic pry tools (I used a LEGO separator!)
6. Small screwdriver set
7. “Helping hands” soldering stand (recommended)
8. Hot glue gun or small screws for final mounting
9. Electrical tape

1. Unplug all cables from your PiDock and Raspberry Pi 400.
2. Remove the RPi 400 from the dock.
3. Disconnect any remaining cables from the PiDock.
4. Open the lid fully. Using a plastic tool, carefully pop off the swivel hinge covers on both sides.
5. With your pry tool, gently release the top edge clips to remove the top cover.
6. There’s a small plastic piece in the center held by double-sided tape - carefully pry it off, keeping the tape intact if possible.
7. Lift off the top panel with the touchpad and set it aside.

1. Use your plastic tool to pop the power connector out from the housing.
2. The connector has heat-shrink tubing over its solder joints — we’ll add new power wires here.
3. Carefully cut and remove the existing heat shrink tubing.
4. Take a clear photo of the wiring for reference before desoldering anything.
5. Desolder the existing wires from the connector.

1. Cut a 3ft (~1m) length of two-conductor AWG16 (~1.5mm) wire (red = +, black = –). Strip both ends.
2. Take the original wires and the new ones and slide heat-shrink tubing onto each wire-pair.
3. Twist each new wire-pair (with its original lead of the same polarity) together.
4. Solder the pairs securely.
5. Solder the new wire bundles back to the connector using your reference photo - on my dock, yellow = positive (outer pin) and black = negative (middle pin).
6. Shrink the heat-shrink tubing for insulation.
7. Reinstall the connector into the case.
8. Make sure the other ends of your new wires don’t touch each other - we’ll connect them later.

1. Plug in your existing (known good) power adapter.
2. The screen should briefly turn on and display Chinese characters (“no signal”).
3. If not: check your solder joints, polarity, and that your power supply works.
4. Once confirmed, disconnect power again.

1. If your buck converter has bulky screw terminals or barrel jacks, desolder and remove them to save space.
2. Check polarity: usually the USB shield is negative (–).
3. “Tin” both the converter’s input pads and your new 12V wires with solder.

1. Position the converter inside the dock. I placed mine to the right of the fan opening to keep airflow clear.
2. Solder the red wire to VIN+ and the black wire to VIN– on the converter.
3. Double-check your polarity using a multimeter before continuing.

1. Connect your new 12V power supply (6A or higher). Check the voltage.
2. The screen should briefly power up.
3. Measure the USB output of the buck converter — it should read around 5.0V.
4. If correct, proceed; if it’s higher than 5.2V, adjust the converter’s trimpot if available.

1. First, connect an RPi 400 to ensure the dock still powers it correctly.
2. Then connect your RPi 500.
3. On boot, you may see:

“This power supply is not capable of supplying 5A. Power to peripherals will be restricted.”

This happens because the buck converter doesn’t advertise its capabilities to the Pi firmware.

You can safely override this warning:

Add this line:

Save and exit. The EEPROM will update automatically.

Reboot the RPi 500 — the warning should now be gone.

1. Power down and unplug the power supply.
2. Secure the buck converter inside the dock using hot glue or small screws.
3. Check that you didn't damaged the hot-glue fastener on the touch pad. I did, so I fixed it immediately.
4. Tidy up the wiring - route the new cable between the two plastic ridges and tape it down neatly.
5. Reinstall the touchpad cover, hinge caps, and reconnect the display cable.
6. Place your RPi 500 in the bay, connect all cables, and close it up.

Power it up — your upgraded PiDock 400 is now fully compatible with the Raspberry Pi 500!

You’ll get proper 5V/5A power delivery and no more warnings.

Enjoy the improved performance and convenience of your new PiDock 500!