● Actively maintained — released 2020, newest ROM build 3 days ago (3 ROMs still current). A phone that still gets updates keeps going long after its manufacturer stops.
Specifications
- SoC
- Samsung Exynos 850
- CPU
- Cortex-A55
- GPU
- ARM Mali-G52 MC2
- Architecture
- arm64
- RAM
- 2/3/4/6 GB
- Storage
- 32/64/128 GB
- Screen
- 6.5" · 720x1600 · PLS LCD
- Battery
- 5000 mAh
- Released
- 2020
3 custom ROMs available
The Samsung Galaxy A21s (codename a21s) has 3 tracked custom ROMs on CustomDroid — including LineageOS, /e/OS, crDroid, running up to Android 16. Each listing links to the project's own download and install guide.
New to flashing? It generally means unlocking the bootloader, booting a custom recovery, wiping, then installing the ROM — exact steps differ per device and ROM, so follow the Install guide for the one you pick, and back up first. New to this? Why flash a custom ROM or read the guides.
LineageOS publishes an official step-by-step install guide for this device: wiki.lineageos.org/devices/a21s.
Support timeline
- Jul 2026LineageOS, /e/OS, crDroid first tracked
Dates show when CustomDroid first indexed each ROM for this device, not when support originally launched.
ROM availability and links come from each project. CustomDroid indexes builds, it doesn't mirror them — always download from the official project, verify the file's hash/signature, confirm it matches your exact codename, and back up before flashing.