[Samsung Galaxy Tab A series Guides, News, & Discus] traman124:
Here's a guide on installing Android 13/14 GSIs on the T290. To install GSIs, you MUST HAVE NOT uploaded past CVG3 (binary version 3). It is advisable that you have an external SD card to transfer GSIs to the tablet (as GSIs can be large).

Steps:

Check if your device is running binary 3 or lower

In the "about this tablet" section of settings, check if the number BEFORE the letter "C" in the build number

Example: T290UES

4

C

WC1 - number 4 before letter C means this is a revision 4 build

If your tablet has a revision 4 or 5 build, do not attempt to do this

Unlock your bootloader (do this on Windows if possible)

Click on the build number 7 times and enter passcode.

Open Settings -> System -> Developer options and enable "OEM Unlocking"

Download Samsung's USB drivers and the latest patched Odin (3.14.1-3B)

Download the unlockable bootloader version

Power off the tablet and boot to download mode (press Vol Up + Vol Down while plugging tablet into a computer). Click Vol Up to confirm download mode

Open Odin and click "BL". Select the file in the open dialog.

Click Start to flash new bootloader. Your device will reboot when this is complete.

Power off the tablet and boot to download mode (press Vol Up + Vol Down while plugging tablet into a computer). Long-press Vol Up to enter the unlock mode.

Allow device to unlock. Your device will be reset at this stage.

Once you reach the "Welcome" screen, turn off your tablet and once again boot to Download mode (press Vol Up + Vol Down while plugging tablet into a computer)

Install TWRP

Download the .tar.md5 for the unofficial TWRP builds for the T290

In Odin, click "AP" and choose the downloaded file. Click Options and disable auto reboot before clicking Start.

Once Odin completes the flash, long press Vol Up + Power. When you see the bootloader unlock warning, briefly let go of Vol Up and press Power and start holding both again after.

You will see the TWRP logo on the screen.

Install LineageOS + the GSI

Download the latest official LineageOS build, your GSI (remember to unzip this), and the multidisabler package (click the source code zip) and place on an external SD card. Place this card inside your tablet.

Click "Wipe" -> "Factory Data Reset" and type "yes"

Click "Install" ->"Change storage" -> "External SD card" -> the LineageOS zip and install it.

If you don't do this step, some GSIs won't boot

Once more, click "Wipe" -> "Factory Data Reset" and type "yes"

Click "Install" ->"Change storage" -> "External SD card" -> the multidisabler and install it.

After the multidisabler has installed, click "Install" ->"Change storage" -> "External SD card" -> "Install Image" and choose your GSI.

Reboot system. Your tablet will boot into your GSI!

Known issues:

Sometimes you wil get an error that a GSI's size exceeds that of your device. If you see this that GSI will not flash.

Sometimes, after installing a GSI, TWRP cannot mount /system. Just wipe /system to fix this before reinstalling a GSI. Installing Magisk and accessing system from Android also works.

Working GSIs:

LineageOS 20.0

LineageOS 21.0

crDroid 10.1 (unofficial)

You tell me

Non-functional GSIs:

Evolution X 14 (ponces's treble build - too large)

Project Elixir 3.13 (stuck on face unlock)

/e/OS 1.17 (bootloop)

Havoc-OS (Android 10) (bootloop)

SGSIs (MIUI, OneUI, Pixel, etc.)

You tell me

Screenshots:

View attachment 6076981