Updating your Raspberry Pi's bootloader
Update the bootloader on a Raspberry Pi 4 so it can start umbrelOS 2.0, and check which version you have
The bootloader is the small piece of firmware that starts your Raspberry Pi and finds its operating system. umbrelOS 2.0 uses a newer disk layout that keeps a spare copy of the system for safe updates, and older bootloaders can't read it. Many Raspberry Pi 4 boards still run the bootloader they shipped with, so update it before you install umbrelOS. It takes about five minutes and only needs a spare microSD card.
A Raspberry Pi 5 usually starts umbrelOS without this step. If an early Pi 5 won't start from your drive, the same update can help.
Signs your bootloader needs an update
Your Pi doesn't start umbrelOS, and you see one of these:
- The green light blinks in a repeating pattern of 4 or 7 flashes.
- A connected screen shows "firmware not found" or "GPT: No bootable partitions".
- The screen stays black, and your Pi never shows up on your network or at http://umbrel.local.
These can have other causes too, but an outdated bootloader is the most common one on a Pi 4.
What you'll need
- A spare microSD card. It will be erased, and any size works.
- A computer with Raspberry Pi Imager installed.
- A screen connected to your Pi (optional), to confirm the update.
Update the bootloader
- Insert the microSD card into your computer and open Raspberry Pi Imager.
- For the device, choose Raspberry Pi 4 (or Raspberry Pi 5).
- For the operating system, choose Misc utility images, then Bootloader (Pi 4 family) (or Bootloader (Pi 5 family)), then USB Boot. If you'll run umbrelOS from a microSD card instead of a drive, choose SD Card Boot.
- For storage, choose your microSD card and write it.
- Unplug any drives from your Pi, insert the microSD card, and power it on.
- Wait at least 10 seconds. When the update is done, the green light blinks steadily without stopping, and a connected screen turns green.
- Power off your Pi and remove the microSD card.
Your Pi is ready. Install umbrelOS as usual by following Installing umbrelOS on Raspberry Pi.
Check your bootloader version
Connect a screen to your Pi and power it on with no microSD card or drive attached. The screen shows the bootloader details, including its date, for example bootloader: 6efe41bd 2022/01/25. After updating, the date should be recent.
If your Pi still doesn't start
- Check the bootloader date again to make sure the update applied.
- Use the official Raspberry Pi power supply. Other supplies, including high-wattage USB-C chargers, often can't power the Pi and a drive at the same time.
- On a Pi 4, plug your drive into one of the blue USB 3 ports.
- Flash umbrelOS onto your drive again, or try a different drive.
If it still won't start, contact us with your Pi model, the bootloader date, what the green light or screen shows, and the drive you're using, and we'll help you from there.