My Raspberry Pi 400 will not boot/is faulty

All Raspberry Pi 400 computers are factory-tested and faults are uncommon. If your Raspberry Pi 400 isn’t starting as expected, the checks below cover the most common causes.

🖥️ Incorrect HDMI port

The Raspberry Pi 400 has two micro‑HDMI ports. If you’re using a single display, connect it to the left port when looking from the rear (your primary output). If you get a blank screen, also double-check your monitor is on the correct input, and make sure the micro‑HDMI plug is fully seated at both ends.

💾 Old or incorrect operating system

Raspberry Pi 400 requires Raspberry Pi OS (formerly “Raspbian”) or another compatible OS image that supports the Pi 400 hardware. If you’re reusing a card from another Raspberry Pi, it may work, but for troubleshooting we recommend starting with a fresh, up-to-date image to rule out configuration and compatibility issues.

If your Pi 400 kit came with a microSD card, it’s typically ready to go with Raspberry Pi OS pre-installed — just make sure it’s inserted properly before powering on.

🔌 Power supply

Raspberry Pi 400 uses a USB‑C power supply rated at 5.1V / 3A (the same spec as Raspberry Pi 4). Some chargers and USB ports can work, but if the supply can’t provide a stable current, you may see random restarts, performance issues, or no boot at all.

For the most reliable setup (especially when using USB devices), we recommend using an official Raspberry Pi power supply.

📦 Boot media not seated (microSD or USB)

Most Raspberry Pi 400 setups boot from a microSD card. Make sure the card is fully inserted into the slot at the rear of the keyboard (it’s a click‑in/click‑out design). We recommend removing it and inserting it again to ensure a solid connection.

Raspberry Pi 400 can also boot from other storage (such as a USB drive), but the storage must be properly imaged and your boot settings may affect which device it tries first.

⚡ microSD card quality

A reliable microSD card makes a big difference to stability. Faster, higher-quality cards (for example, Application Performance Class A2) are less likely to cause slow boots, crashes, and file corruption over time.

🧰 Corrupted OS install (reflash your boot media)

Sometimes an operating system install can become corrupted (for example, after an unexpected power loss). A quick way to rule this out is to reflash Raspberry Pi OS onto your microSD card (or USB drive) using Raspberry Pi Imager.

If you don’t have a built-in card reader on your computer, you’ll need a USB microSD card reader to write the image.

💡 Check the indicator LEDs

The LEDs on Raspberry Pi 400 can help narrow down what’s happening during boot. If the LED flashes in a repeating pattern, you can compare it to Raspberry Pi’s official LED warning flash codes. For example, 0 long flashes + 8 short flashes indicates an SDRAM failure (if this persists across different boot media and with minimal peripherals connected, please contact us).

🛟 Still no signs of life?

If you’ve tried the steps above (especially checking HDMI0, using a known-good power supply, and testing with freshly-imaged boot media) and the Pi 400 still won’t boot, please contact us with as much detail as you can — including your order number, which power supply you’re using, what storage you’ve tried, and any LED behaviour you can see.