In this article, I want to share my experience with successfully installing a custom ROM on my Samsung Galaxy A7 Lite(SM-T220). The process will be similar to that of other Samsung devices, too. If you want to make your android device faster without Samsung preinstalled apps, it is good idea to consider installing custom OS in your device.
My preferred operating system is Ubuntu, so I have this on my Ubuntu system, the process should be similar to other Linux variant operating systems.
Ubuntu Environment Setup
- Install core Android and Samsung flashing dependencies on Ubuntu
sudo apt install dab, fastboot, p7zip-full, libusb- Download odin4 binary tool from the link below (or can be used another links)
https://github.com/Adrilaw/OdinV4/releases
The downloaded zip file is extracted and made executable. The executable binary is copied into /usr/local/bin folder so that odin4 command can be accessed from anywhere.
chmod +x odin4
sudo mv odin4 /usr/local/bin- Add dev rules for USB for Samsung devices in Ubuntu. Create/append a file /etc/udev/rules.d/51-android.rules with the following content:
SUBSYSTEM=="usb", ATTR{idVendor}=="04e8", MODE="0666", GROUP="plugdev"- [optional?] To prevent USB communication timeout errors with Samsung Download Mode.
sudo rmmod cdc_acmUnlocking Bootloader & Download Mode
- Enable Developer Options, and then USB Debugging & OEM Unlocking from stock Adroid settings.
- Boot into Download Mode (Vol Up+Vol Down + USB Cable connected to Ubuntu), and then long press Volume Up to unlock bootloader.
- You can use command “adb devices” to check if he device is properly connected. In any case if the device bootloader not roperly unlocked, you can simply use the following command: “adb reboot download”. This will reboot in download mode.
- If the device is showing as “unauthorized”, then you check the tablet and allow USB debugging.
- The adb server can be restarted using “adb kill-server; adb start-server”
Flash custom TWRP Recovery
- Download TWRP Recovery from this link: https://github.com/gta7lite/teamwin_device_samsung_gta7lite/releases
- Run this command: “sudo odin4 -a TWRP_v2.2_gta7lite.tar”. Make sure it successfully flashed. In case any problem, check the bootloader is properly unlocked.
- Do force reboot (Power+ Vol Down) and then immediately Power+ Vol Up to catch to recovery mode. (Note: if you are late to press Power+ Vol Up, then stock Android could overwrite TWRP. If so, before booting stock Anroid, do force reboot and to go recovery mode)
TWRP Fastboot Mode
- From TWRP recovery mode, boot into Fastboot Mod (Reboot > Fastboot) to access the device’s dynamic partition layout via terminal.
- Run these commands to clear system space and partition to make room for the new OS. “fastboot erase system; fastboot erase product; fastboot resize-logical-partition product 0x0“
Download, Flash & Boot
- I preferred LineageOS21 (Android 14) GSI (generic system image)image which is lightweight and appropriate for a slow devices like Galaxy A7 Lite.
- Download the image from the following location: https://sourceforge.net/projects/andyyan-gsi/files/lineage-21-td/lineage-21.0-20250621-UNOFFICIAL-arm64_bgN-signed.img.gz/download
- If you want to build the image yourself: https://github.com/Adrilaw/OdinV4 or list of already built images: https://sourceforge.net/projects/andyyan-gsi/files/
- The downloaded *.img.gz file should be extracted into *.img format (gunzip lineage-21.0-20250621-UNOFFICIAL-arm64_bgN-signed.img.gz)
- In fastboot mode, you can flash the image using this command: “fastboot flash system lineage-21.0-20250621-UNOFFICIAL-arm64_bgN-signed.img“
- After flashing completes, disconnect the USB, reboot back into TWRP recovery (Power+Vol Down, then Power+Vol Up) and Format Data to wipe factory encryption(Wipe > Format Data), and reboot the system.
The initial boot could take 3-5 minutes, so have patience!
Congratulations! You have successfully installed custom OS into your Samsung device!!!