Samsung Galaxy J6 Plus (samsung-j6primelte)

From postmarketOS Wiki
Samsung Galaxy J6+
Galaxy J6+ running Weston
Galaxy J6+ running Weston
Manufacturer Samsung
Name Galaxy J6+
Codename samsung-j6primelte
Released 2018
Type handset
Hardware
Chipset Qualcomm Snapdragon 425 (MSM8917)
CPU Quad-core 1.4 GHz Cortex-A53
GPU Adreno 308
Display 720x1480 IPS
Storage 32 or 64 GB
Memory 3 or 4 GB
Architecture armv7
Software
Original software Android
Original version 8.1
Extended version 10
postmarketOS
Category testing
Pre-built images no
Mainline no
Features
Flashing
Works
USB Networking
Works
Internal storage
SD card
Battery
Partial
Screen
Works
Touchscreen
Works
Multimedia
3D Acceleration
Broken
Audio
Partial
Camera
Camera Flash
Connectivity
WiFi
Works
Bluetooth
GPS
NFC
Modem
Calls
SMS
Mobile data
Miscellaneous
FDE
USB OTG
HDMI/DP
Sensors
Accelerometer
Magnetometer
Ambient Light
Proximity
Hall Effect
Haptics
Barometer


Contributors

Users owning this device


How to enter flash mode

  1. Turn off your Galaxy J6+.
  2. Hold the Volume Down and Up buttons, and plug in a USB cable to a computer.
  3. Let go of the Volume buttons once you see the download mode confirmation menu.

How to unlock OEM

Via Android Settings

  1. Go to Android settings.
  2. Select "Developer options". If you haven't enabled developer options, then refer to the following steps:
    1. In Android settings, select "About phone".
    2. Select "Software information".
    3. Locate "Build number" and tap on it 7 times.
  3. Locate "OEM unlocking" and toggle it on (this will perform a reset, so backup any valuable data). Sometimes this option is unavailable or greyed out, but there exist methods that attempt to bring it back (various instructions to do so can be found on the web).

Other Ways

If your Android system is unusable, you can try flashing the stock ROM in order to try putting a usable system back on the phone and proceeding with the instructions for unlocking via Android settings. Stock ROMs can be downloaded from various sources online. Picking the right ROM/firmware can be tricky, as they are model-specific. Even ROMs that match your model can have different bootloader versions, which must be appropriate to the "fused" version in order to work correctly[1]. Here is an example firmware version (bootloader version in bold): J610FXXU7CUF1

Some phones can be "OEM unlocked" using fastboot.

Installation

  1. Run pmbootstrap init. Make sure you set the manufacturer to samsung, and the codename to j6primelte.
  2. Run pmbootstrap install.
  3. Run pmbootstrap export.
  4. Unlock OEM if you haven't already.
  5. Reboot to download mode using the steps above.
    1. If you want to install the rootfs to system, run heimdall flash --BOOT /tmp/postmarketOS-export/boot.img --SYSTEM /tmp/postmarketOS-export/samsung-j6primelte.img.
    2. If you want to install the rootfs to userdata instead for more disk space, run heimdall flash --BOOT /tmp/postmarketOS-export/boot.img --USERDATA /tmp/postmarketOS-export/samsung-j6primelte.img.

Entering SSH

  1. Plug in your phone to your computer. It should show up as a USB RNDIS host.
  2. Check what the RNDIS host is registered as using the ip link command. In my case, it's enp0s20f0u3.
  3. Run sudo ip link set enp0s20f0u3 address 02:01:02:03:04:08, replacing enp0s20f0u3 with the output from step 2.
  4. You should be now able to SSH to your phone via ssh user@172.16.42.1.

What doesn't work

  • Hardware acceleration is broken due to no /dev/dri/, there's only /dev/fb0 (and /dev/fb1, but it's not used as the main display).
  • charging-sdl doesn't work due to DirectFB crashing with:
(!) DirectFB/FBDev: Could not disable console acceleration!
    --> Invalid argument
(!) DirectFB/Core: Could not initialize 'system_core' core!
  • Xorg doesn't work either with a similar error:
[    19.023] (EE) FBDEV(0): FBIOPUT_VSCREENINFO: Invalid argument
[    19.023] (EE) FBDEV(0): mode initialization failed
[    19.023] (EE) 
Fatal server error:
[    19.023] (EE) AddScreen/ScreenInit failed for driver 0
  • ALSA sees the audio devices but can't manage them (we need to xml2uml the mixer_paths.xml most likely)

Notes

  • Wi-Fi works only with the firmware blobs
  • Audio partially works only with the firmware blobs
  • DRM MSM drivers refuse to build on the downstream kernel[2], for now requires mainlining or patching
    • DRM itself builds fine, but it's not of much use without DRM MSM drivers

See also

Footnotes

  1. ↑ https://www.arencambre.com/2018/01/01/fused-firmware-version-locks-samsung-s7/
  2. ↑ https://twitter.com/omametech/status/1427977023767580672
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