Samsung porting notes, a loose collection


  • Infrastructure

    Unordered collection of my Samsung porting notes

    Bootloader and Recovery
    Samsung devices are similar to other Android devices, but not equal. The bootloader also uses a boot and recovery partition, but its not possible to use fastboot to flash those.
    Instead, the device needs to be brought into "Download Mode". This can be achieved by:

    • Manually by pressing Vol-Down, Home and Power button until the green warning text appears
    • By issuing adb reboot download command

    This mode can only be used together with Odin on Windows or Heimdall on Linux. Both are the "inofficial" tools used by everybody. So no worries, its not a harmful software. While Odin requires all image files to be wrapped in tgz files, Heimdall will be happy with plain img files.

    Specifically for younger models both software should be on a recent level. Ubuntu´s ppa holds an older version of Heimdall, but its best to not use is. Instead, git clone it from here: https://github.com/Benjamin-Dobell/Heimdall.git and build it from its sources.

    Note: Often you will find instructions on Samsung ROMs saying that you need to obtain a PIT file before flashing a device. That is not required and in fact can soft-brick your device as the PIT file is the partition table and is only necessary when repartitioning. We dont need that normally and its more safe not to download any bogus PIT files and mess with them.

    Heimdall will always reboot by default after flashing. That´s a bit annoying. Even with --no-reboot it will leave the connection in a strange state. So after flashing an img file its not possible to immediately push a second one. We will need to take care of this behaviour also in the installer. We also cannot tell Heimdall to reboot into recovery for example.

    The commands for flashing are:

    heimdall flash --BOOT ubports-boot.img
    heimdall flash --RECOVERY ubports-boot.img



  • @flohack said in Samsung porting notes, a loose collection:

    Instead, the device needs to be brought into "Download Mode". This can be achieved by:

    Manually by pressing Vol-Down, Home and Power button until the green warning text appears

    On my Samsung Galaxy S8, there is no physical home button, only virtual on the display.
    I figured out, instead of the Home-Button, I need to press the Bixby button, below Vol-Down,
    then the green warning text appears...


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