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5 min read

Updating an old Galaxy to Android 16

Halfway through 2026, I swapped my good old Samsung Galaxy M31, which I bought in 2020, for a Xiaomi Poco X8 Pro. It sat in a drawer while I kept thinking about something to do with it. The phone was stuck in time, stuck on Android 12 for at least 3 years, with no security update support from Samsung whatsoever.

I already knew about the crDroid project through a friend from work. crDroid is an open-source custom ROM for Android based on Lineage OS, maintained by the community. This ROM is highly customizable and free of bloatware from Google or the manufacturer, which tends to slow the phone down.

I had recently rooted this same phone, and we were discussing the difficulties that causes, because of the blocks on banking apps and gov.br, when crDroid came up again and I decided to check the site to see if there was support for my Galaxy M31. And wouldn't you know it, a new version had just been released.

Once I got home, I decided to try it out to see how it works. I downloaded the ROM from the official site for my phone model, and downloaded MindTheGapps (recommended by the ROM maintainer for the Galaxy M31), a package that installs Google's apps and services on custom Android ROMs, since Google doesn't officially support these systems.

I connected the phone to my PC and used Odin, software created by Samsung, to flash the custom recovery mode. Then I put the device back into flash mode and used adb to send over the crDroid ROM and the MindTheGapps package. In no time my phone jumped from Android 12 to Android 16, gaining features it didn't originally have, like face unlock.

I haven't had time to test it in much depth yet, but besides face unlock, the system also got a new settings menu, crDroid Settings, which lets you heavily customize Android and its interface, from the status bar, where the wi-fi and battery icons live, to adding button shortcuts and special gestures.

I'm now testing open-source apps that, combined with Shizuku and Dhizuku, unlock new possibilities by exposing privileged permissions that Android normally blocks, like freezing or disabling system apps, customizing the interface without root, and automations.

crDroid: pros and cons

For anyone thinking about doing the same, it's worth weighing what you gain and what you lose:

Pros

  • Performance and smoothness: the system becomes extremely light, with none of the stutters from the old One UI and no factory bloatware running in the background.
  • Up-to-date security: Android 16 security patches on a phone abandoned by the manufacturer.
  • New features: native Android 16 features (like face unlock support built right into the ROM, improved privacy, and granular permissions).
  • Full customization: the crDroid Settings panel lets you change absolutely everything in the interface without needing root.

Cons

  • Permanent loss of Knox: blowing the e-Fuse permanently disables native features like Samsung Pass, Secure Folder, and Samsung Pay.
  • Stock camera quality: the default AOSP camera app tends to be simpler than Samsung's (which can be worked around by installing a GCam).
  • Play Integrity / banking apps: without extra tweaks (like hiding modules), apps that require strict security checks (like banks and Gov.br) may refuse to work.

Installing crDroid

For anyone curious about the "behind the scenes" of what I did, there was no mystery to the process, but it does require a well-defined sequence in the correct order:

  1. Unlock the bootloader: this step is done in the developer options menu, unlocking the phone to accept software not signed by Samsung. Keep in mind this voids the product's warranty.
  2. Flash the custom recovery mode via Odin: just put the device into Download mode and send over the recovery.img and vbmeta.img files via Odin (or heimdall-flash on Linux). On the Galaxy M31, Download mode is accessed with the device turned off, by holding both volume buttons and then connecting the device to the computer via cable.
  3. Flash the crDroid ROM and MindTheGapps: access recovery mode (Vol. Up + Power button with the phone connected to the PC), factory reset, and use adb sideload to load the ROM file and MindTheGapps, one at a time.

After that it was just a matter of restarting the phone, adding my Google account, going through the basic system setup, and I was already having fun customizing my phone's entire interface.

Conclusion

Seeing a 2020 mid-ranger running the latest version of Android this smoothly shows the value of the open-source community. My old phone, forgotten in a drawer, turned into a perfect device for testing, development, and use as a backup phone.

If you have a phone gathering dust that's supported by crDroid, it's well worth taking a weekend to try it out!

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