If you’re using a Samsung Galaxy A21s and want to breathe new life into your device, installing an Android 16-based custom ROM is a solid move. Google recently...
Mohammed Huwais
Last updated on October 27, 2025
Mohammed Huwais
Author
I started my career as a blogger in 2014 and also worked on an Android niche platform to gain extra income. I cover the topic on How to guides, software updates, Custom ROM updates and also product review. I'm 24 years old, completed MBA (Master of Business Administration) from Sikkim Manipal University.
If you’re using a Samsung Galaxy A21s and want to breathe new life into your device, installing an Android 16-based custom ROM is a solid move. Google recently released Android 16 for Pixel devices, and developers have already ported unofficial AOSP builds to older phones like the Galaxy A21s. In this guide, you’ll learn how to safely install Android 16 on Galaxy A21s and enjoy its latest features.
The Samsung Galaxy A21s is having Samsung’s new Exynos 850 octa-core chipset coupled with RAM options from 3 to 6 GB. The phone has storage options to choose between 64 and 128 GB which is expandable by a MicroSD card up to 512 GB. The phone has a massive 5000 mAh of battery which can be charged using a 15w fast charger that comes in the box. It has a 3.5mm headphone jack as well.
The Samsung Galaxy A21s has a 6.5-inch HD+ 720p resolution super AMOLED display with a punch-hole camera cut out which Samsung calls its infinity-o display. The phone has an aspect ratio of 20:9 and the screen-to-body ratio is around 83%. It has a pixel density of around 270 Pixels per inch (PPI). The phone weighs around 192 grams due to its big battery and its thickness is around 8.9mm.
The phone runs on Android 10 based on Samsung’s One UI 2.0. It has features like dark mode, Android 10 gestures, and better one-handed usage. Galaxy A21s features a rear-mounted fingerprint sensor along with a facial recognition system for the security of the device. It also supports DUAL nano-SIM for connectivity.
The Quad-camera setup of the Galaxy A21s consists of a 48 MP main camera with PDAF, then there is an 8 MP ultrawide sensor, followed by a 2 MP macro and 2 MP depth sensor along with LED flash. It can record videos at 1080p @ 30fps. The phone has HDR and Panorama shooting options as well. At the front, there is a 13 MP selfie shooter in a punch-hole design, it can also record videos at 1080p @ 30 fps
Android 16 introduces Material 3 Expressive, a refined evolution of Google’s design language for smartphones and tablets. While it doesn’t completely reinvent the interface, it represents one of the most noticeable user-facing changes in the OS. Rather than a dramatic visual overhaul, Material 3 Expressive enhances the foundation laid by Material Design 3 by introducing smoother, more dynamic animations, larger touch targets, and bolder typography.
This update arrives at a perfect moment. Material Design 3, first introduced with Android 13, had begun to feel dated. Material 3 Expressive breathes new life into the interface while preserving the familiar look and feel users have grown comfortable with. Instead of overhyping the changes, Google’s own animations showcase the polish and fluidity of this next step in Android design.
Android 16 introduces a wealth of new features, system optimizations, and UI refinements. Some of the highlights include:
These updates aim to improve user experience across different types of devices, including foldables, tablets, and standard phones.
Although Android 16 is rolling out first to Pixel devices, many brands like Xiaomi, OnePlus, Samsung, Realme, and others will follow soon. If you’re impatient, a custom ROM is the best way to get Android 16 today.
Everything seems to be working fine.
If you spot any bugs, report them along with proper logs to the developer.
Always back up your device before flashing any ROM. This prevents data loss if anything goes wrong. Backup guide here.
Charge your phone to at least 50% to avoid shutdowns during the flashing process.
You can skip this part if you have already installed TWRP Recovery on your Galaxy A21s. For those who haven’t, ADB and Fastboot commands (platform-tools) are required to boot your device into bootloader mode, allowing you to perform the necessary flashing operations. ADB (Android Debug Bridge) establishes a connection between your device and computer, while Fastboot is a more advanced command-line utility for flashing and modifying Android devices.
You can download the ADB and Fastboot Binaries (Platform-Tools) here.
You’ll need the appropriate USB drivers to ensure a successful connection between your Galaxy A21s and your computer. These drivers enable file transfers, flashing, and other operations between your devices.
You can download the latest Samsung USB drivers here.
Unlocking the bootloader of your Galaxy A21s. is essential before you can install any custom ROM. Make sure to follow Samsung’s official instructions for unlocking the bootloader. Unlocking the bootloader will wipe your device, so back up your data beforehand.
You must install TWRP Recovery on your phone to install any custom ROM on your device. After unlocking the bootloader, follow our guide to install TWRP Recovery on your Galaxy A21s.
You can download the Android 15 custom ROMs for the Samsung Galaxy A21s from the links below:
| OS | Download Link |
| Evolution X | Download |
| CrDroid OS | Download |
Most AOSP ROMs don’t come with Google apps. You’ll need to flash Android 16 GApps separately.
Note: Flash GApps right after flashing the ROM. Don’t reboot in between.
Warning!
GetDroidTips is not responsible for any issues that may happen to your device if you flash it on another device and brick it. Do it at your own risk.
adb reboot recovery
The first boot after installing a custom ROM may take a bit longer than usual, so don’t panic if it seems slow. After the device boots, you will need to set it up as a new device, just like when you first got it.
By flashing Android 16 on your Galaxy A21s, you’re extending its life and unlocking modern Android features that Samsung may never officially provide. While this is an unofficial AOSP build, early reports suggest solid stability. That said, bugs may still appear, so always report them with logs to help developers improve the experience.
If you have questions or run into issues during installation, feel free to drop a comment. Enjoy your fresh Android 16 experience!
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