Flashing the Reference Hardware
Tablet specifications
The tablet we are using is a Samsung Galaxy Tab S5e WiFi (SM-T720). This tablet is available in 2 variants:
- 4GB RAM and 64GB internal storage
- 6GB RAM and 128GB internal storage
Both variants will work with our OTA image but preference should be given to the 128GB (with 6GB RAM) variant, which allows to run TomTom Digital Cockpit / Cluster app on multiple screens without memory issues.
Note: The Galaxy Tab S5e LTE (SM-T725) is not supported by our OTA image!
Image modifications
The image we flash on the Samsung Galaxy S5E tablet is based on version 19.1 of LineageOS, which in turn is based on Android 12. The image is customized for our own use cases, main modifications are as follows:
-
Added a TomTom Digital Cockpit placeholder system app, to give developer builds access to system-only permissions:
- multimedia browsing
- virtual display
- call management
-
Replaced the platform key with the TomTom Digital Cockpit key, so that TomTom Digital Cockpit is recognized as a system app and is granted system permissions.
-
Modified the LineageOS updater app to download and install OTA updates from TomTom's Artifactory server (this modification is for internal use only)
-
Enabled Bluetooth audio profiles for cars (for example, the target behaves as BT speakers):
- A2DP profile in sink mode
- HandsFree profile in HandsFree mode
- PBAP client
-
Added Android Auto features:
- android.car.* APIs
- media browsing
This guide explains how to install and use the customized TomTom Digital Cockpit image on a new Samsung Galaxy Tab S5e tablet.
Prerequisites
Currently, the initial flashing procedure requires the availability of:
- A Windows machine.
- The
adb
tool, installed on any machine, it doesn't have to be the Windows machine above.
Step-by-step installation guide
Note: If the tablet has already been flashed with the LineageOS image, it can be upgraded by following the instructions in Upgrade Tablet.
TomTom takes no responsibility for any damage that may occur from installing or using the following freely available third-party tools and files.
The instructions are based on the official LineageOS installation instructions:
To prepare, download the following files:
- Odin (Samsung flashing tool)
- TWRP (Team Win Recovery Tool) (download the latest
img.tar
file) - Samsung USB drivers
- vbmeta.tar
Then, follow these steps:
-
Download the latest release of the OTA image (file ending with -
ota.zip)
from here. -
Install the Samsung USB drivers and the Odin tool on your Windows machine.
-
Power on the tablet and go through the initial setup if it's the first time it's being powered on. You can skip as many steps as you can.
-
Connect the tablet to a WiFi network.
This step is necessary for showing the
OEM unlock
option below. -
From the
Settings
app, selectAbout tablet
→Software Information
, then tap 7 times onBuild number
to enable theDeveloper Options
. -
From the
Settings
app, enableDeveloper Options
→OEM unlock
. If this option is not visible, make sure that you have a working WiFi connection and open theDeveloper Options
menu again. -
Power off the tablet by long pressing the
Power
button andVolume Down
button together, and then tapping onPower off
. -
Press the
Power
,Volume Up
andVolume Down
buttons at the same time and, while keeping the buttons pressed, plug the USB cable into the Windows machine. The tablet should show a blue screen (Samsung's download mode) showing the option to unlock the bootloader, as in the image below. -
Long press the
Volume Up
button to select theUnlock bootloader
page. The image below will be shown: -
Press the
Volume Up
button again to finally unlock the bootloader. The device will perform a factory reset and restart into Android. -
Repeat steps 3, 4, 5 and verify that the
OEM Unlock
option is still enabled in theDeveloper options
menu. -
Ensure that the tablet is connected to WiFi and that the
OEM unlock
option is visible, otherwise the next steps might fail! -
Power off the tablet by long pressing the
Power
button andVolume Down
button and then tapping onPower off
. -
Press the
Power
,Volume Up
andVolume Down
buttons at the same time and, while keeping the buttons pressed, plug the USB cable into the Windows machine. The tablet will show the blue screen (Samsung's download mode) again. -
Alternatively, steps 13 and 14 can be skipped. Enable the
USB debugging
option in theDeveloper options
menu, and run this command instead:adb reboot download
. -
Start the Odin tool that you previously installed on the Windows machine.
-
Check that you see a valid device in the top left corner of the Odin window. It will show up as something like
COM1
; the number afterCOM
can be any. -
Check the box next to the button labeled
AP
, and then click theAP
button. -
A pop-up dialog will ask you to select a file. Select the previously downloaded vbmeta.tar file and press the Start button. A blue transfer bar will appear on the device showing the
vbmeta
image being flashed. After that, the device will reboot. -
The device will fail to restart; this is expected. It will show the option to perform a factory reset. Perform the factory reset by pressing the
Volume down
button followed by thePower
button. -
Confirm the selection by pressing the
Volume down
button followed by thePower
button. -
Repeat steps 11, 12, 13, 14, 15, 16, 17, 18.
-
This time, when asked to select a file, select the previously downloaded
TWRP
file. -
Press the Start button and keep the
Volume Up
button pressed while the file is being flashed and the tablet reboots.
The tablet should now reboot into recovery: theTeam Win Recovery Project
tool (TWRP
).
Note: Be sure to reboot into recovery immediately after installingTWRP
. If you don’t, the custom recovery will be overwritten on boot. -
The recovery tool will ask whether to keep System Read Only, as shown in the image below.
Check the Never show this screen during boot again box and swipe the bottom bar to allow system modifications.
-
Tap
Wipe
. -
Now tap
Format Data
and continue with the formatting process. This will remove encryption and delete all files stored in the internal storage. -
Return to the previous menu and tap
Advanced Wipe
, select theCache
andSystem
partitions, and thenSwipe to Wipe
. -
Sideload the LineageOS
.zip
package:- On the device, select
Advanced
→ADB Sideload
, then swipe to begin sideload. - On the host machine, sideload the package using:
adb sideload lineageos-gts4lvwifi-<version>-ota.zip
This is the file you downloaded from here.
- On the device, select
-
On the device, select
System
→Reboot
. The tablet will now reboot into the custom TomTom Digital Cockpit image. -
Congratulations!
Upgrade Tablet
If the tablet has already been flashed with the LineageOS image, it can be upgraded with any
machine that has adb
installed, using the following command:
1adb root2adb push lineageos-gts4lvwifi-<version>-ota.zip /data/lineageos-gts4lvwifi-ota.zip && \3 adb shell "echo --update_package=/data/lineageos-gts4lvwifi-ota.zip > /cache/recovery/command" && \4 adb reboot recovery