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Installing CM5 eMMC OS

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Rijndael edited this page Nov 5, 2026 · 2 revisions

💽 Installing an Operating System on CM5 eMMC

If your piBrick PocketCM5 uses a Raspberry Pi CM5 with onboard eMMC storage, you can install or replace its operating system directly on the eMMC using Raspberry Pi's rpiboot tool.

Unlike the recommended CM5 Lite configuration, eMMC storage is built into the module. You cannot remove it like a microSD card, so installing or changing the OS requires connecting piBrick to a host computer and exposing the eMMC as a USB mass-storage device.

📋 Before You Begin

Prepare the following:

  • A piBrick PocketCM5 with a CM5 variant that includes onboard eMMC.
  • A computer running Linux, Windows or Mac.
  • A USB data cable compatible with the piBrick boot connection.
  • A compatible operating system image.
  • The Raspberry Pi rpiboot tool.

Warning: Flashing an OS can erase the existing contents of your eMMC. Back up any important files before proceeding.

🔌 1. Enter piBrick Boot Mode

piBrick provides a hardware button sequence to enter CM5 USB boot mode.

  1. Make sure piBrick is powered off.
  2. Connect the top USB-C port on piBrick to your host computer using a USB data cable. This port is required for the eMMC flashing process.
  3. Press and hold the User side button at the top-right corner of piBrick.
  4. While continuing to hold the button, power on piBrick.
  5. Keep the button held during the boot-mode entry sequence, then release it.

piBrick should now be ready for the host computer to communicate with the CM5 through rpiboot.

💻 2. Install and Run rpiboot

rpiboot is Raspberry Pi's USB boot utility. It loads the necessary boot software so the CM5's onboard eMMC can be accessed from a host computer.

Official resources:

Choose the instructions for your host operating system.

Linux

On Debian or Ubuntu-based systems, install rpiboot:

sudo apt update
sudo apt install rpiboot

Run the tool:

sudo rpiboot

If the device is not detected, check the USB connection and repeat the boot-mode entry sequence. Depending on your host and software version, you may need to start rpiboot before entering boot mode.

Windows

  1. Open the Raspberry Pi usbboot releases page.
  2. Download and install the appropriate Windows rpiboot package.
  3. Follow the installer instructions, including any required driver installation or restart.
  4. Launch the available rpiboot - Mass Storage Gadget utility.
  5. Connect piBrick using its top USB-C port and enter boot mode using the button sequence described above.
  6. Wait for the CM5 eMMC to appear as a USB mass-storage device.

The exact application name or interface may differ between releases.

macOS

  1. Follow the official Raspberry Pi usbboot instructions to install or build rpiboot for macOS.
  2. Open Terminal and run the rpiboot command using the method described in the repository's macOS instructions.
  3. Connect piBrick using its top USB-C port and enter boot mode using the button sequence described above.
  4. Wait for rpiboot to complete and for the CM5 eMMC to appear as a storage device.

Installation requirements and commands can vary by macOS version. Refer to the official repository for the latest instructions.

💾 3. Flash the Operating System

After rpiboot exposes the eMMC as a USB mass-storage device, you can write an operating system image to it.

The easiest method is to use Raspberry Pi Imager:

  1. Download and open Raspberry Pi Imager.
  2. Use Ctrl+Alt+S to open the debug menu. Scroll down to Advanced Options and ensure Enable Rpiboot/Fastboot Support is enabled. rpiboot must be installed for this to work.
  3. Select the operating system you want to install, or choose a compatible custom image.
  4. Select the storage device corresponding to the CM5 eMMC.
  5. Carefully verify that you selected the correct device.
  6. Start writing the image and wait until the process finishes successfully.

⚠️ Important: Make sure you select the CM5 eMMC, not your computer's internal drive, another external disk, or a microSD card. Writing the image erases the selected storage device.

For advanced users, Raspberry Pi also documents writing raw OS images directly to the exposed storage device. See the official eMMC flashing instructions.

🚀 4. Boot from eMMC

After the image has been written:

  1. Wait for the imaging process to complete.
  2. Safely disconnect or eject the eMMC storage device from the host operating system, if applicable.
  3. Disconnect the USB data cable from piBrick.
  4. Power-cycle piBrick normally without holding the User side button.
  5. Allow the CM5 to boot from its onboard eMMC.

If the device does not boot, verify that the OS image is compatible with CM5 and check the boot configuration.

⚙️ 5. Install the piBrick Linux Drivers

After Linux boots successfully, install the piBrick drivers to enable the supported hardware features.

Follow the Quick Start Guide.

🛠️ Troubleshooting

  • The eMMC does not appear: Check that you are using a USB data cable and the correct piBrick USB connection. Repeat the boot-mode entry sequence and restart rpiboot if necessary.
  • The computer does not detect piBrick: Try another USB port or connect directly to the computer instead of using a USB hub.
  • The flashing process fails: Verify the selected storage device, check the OS image, and consult the official rpiboot troubleshooting guide.
  • The OS does not boot after flashing: Confirm that the image supports CM5 and that the device is no longer entering boot mode.

Additional resources:

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