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Tablet reflashing

A guide to flashing Linux onto older tablets using alternative bootloaders, device-specific images and flashing tools.

References

Section titled “References”

Samsung tablets

Section titled “Samsung tablets”

  1. Download lk2nd

    Section titled “Download lk2nd”

    Open the GitHub releases page and download lk2nd-msm8916.img. This image provides an alternative bootloader that will be used to start the Linux installation.

  2. Download Heimdall

    Section titled “Download Heimdall”

    From the GitHub releases, download heimdall-2.0.2-macos-arm64.tar.xz. Heimdall is the utility used to flash the bootloader image to the tablet.

  3. Extract Heimdall

    Section titled “Extract Heimdall”

    Open a terminal in the directory containing the downloaded archive, then extract its contents. Make sure you run subsequent commands from a location where the extracted Heimdall files are accessible.

    Terminal window
    tar -xf heimdall-2.0.2-macos-arm64.tar.xz

  4. Remove the macOS quarantine attribute

    Section titled “Remove the macOS quarantine attribute”

    macOS may flag downloaded applications because they came from the internet. This command removes the quarantine attribute from the Heimdall frontend application so it can be launched.

    Terminal window
    sudo xattr -d -r com.apple.quarantine ~/Downloads/heimdall-frontend.app

  5. Download the Linux images

    Section titled “Download the Linux images”

    Open the Nura image directory and download both files:

    • 20261009-0946-postmarketOS-v26.06-phosh-29.1-samsung-gt510-boot.img.xz
    • 20261009-0946-postmarketOS-v26.06-phosh-29.1-samsung-gt510.img.xz

    The boot image contains the files needed to start the system, while the main image contains the postmarketOS installation. Keep both files together with the downloaded lk2nd image for the following steps.

  6. Extract the boot image

    Section titled “Extract the boot image”

    Decompress the boot image archive. This produces the uncompressed boot image required by the boot command later in the guide.

    Terminal window
    xz -d *-boot.img.xz

  7. Extract the system image

    Section titled “Extract the system image”

    Decompress the main postmarketOS image. This produces the image that will be written to the tablet’s userdata partition.

    Terminal window
    xz -d *-samsung-gt510.img.xz

  8. Enter Samsung Download Mode

    Section titled “Enter Samsung Download Mode”

    Before flashing the bootloader, put the tablet into Download Mode so Heimdall can communicate with it.

    1. Power off the tablet completely.
    2. Hold Volume Down + Home + Power simultaneously until the cyan warning screen appears.
    3. Press Volume Up to confirm and enter Download Mode. The screen should display a green Android robot and a “Downloading…” message.
    4. Connect the tablet to your Mac using a USB cable.

  9. Flash the bootloader

    Section titled “Flash the bootloader”

    Put the tablet into the appropriate download mode and connect it to your Mac before running this command. It flashes the lk2nd image to the tablet’s BOOT partition using Heimdall.

    Terminal window
    ./heimdall-frontend.app/Contents/MacOS/heimdall flash --BOOT lk2nd-msm8916.img

    Wait for the flashing process to finish before disconnecting the device. If Heimdall cannot detect the tablet, check the USB connection and confirm that the device is in download mode.

  10. Flash the Linux system image

    Section titled “Flash the Linux system image”

    With the tablet in the appropriate fastboot mode, write the extracted system image to the userdata partition. This replaces the existing user data, so make sure you have backed up anything you want to keep.

    Terminal window
    fastboot flash userdata *-samsung-gt510.img

  11. Boot Linux

    Section titled “Boot Linux”

    Start the tablet using the extracted boot image. This command boots the supplied image directly rather than flashing it as a separate step.

    Terminal window
    fastboot boot *-boot.img

    Allow the device time to start. The first boot may take longer than subsequent boots, so give it a little time before troubleshooting.

  12. Log in to the system

    Section titled “Log in to the system”

    When the initial login prompt appears, use the default passcode below.

    Default passcode: 147147

    Once logged in, verify that the system starts correctly and that the Phosh interface is usable. Change any default credentials if the installed system provides a supported way to do so.