Part of Pixel Experience guides, 2025 guides.

There is a specific kind of person who tries this ROM. You like Android, you have used a couple of custom builds, and you have started to notice that most of them add something. A theme engine here, a pile of extra settings there, a launcher you did not ask for. Halcyon OS goes the other way.

This is an official Android 16 build for the Poco X7 Pro. Official matters. It means the build comes from the team rather than a random port someone uploaded, and it means updates are more likely to keep arriving instead of dying after one release. That alone puts it ahead of half the zips floating around for this phone.

I flashed it clean and used it properly, so this is what it looks like, what works, what does not, and who should have it on their phone.

What it looks like

Stock Android 16, and I mean that. The notification shade looks right. Quick tiles behave the way you expect. The settings app is laid out the normal way, so you are not relearning where everything lives. If the last ROM you tried had its own idea about how a settings menu should work, the first ten minutes here feel like coming home.

The launcher is plain and the icon set is default. No heavy skin, no restyled system apps, no extra home screen panes you have to delete. It is the Android that Google ships, minus the parts that a Pixel gets and your phone does not.

How the flash goes

The route here is the vendor_boot method followed by a sideload. That is the standard Android 16 flow for this device and it is not scary once you have done it once.

• Flash the vendor_boot image from the vendor package in fastboot.
• Reboot straight into recovery, holding the volume key the moment the screen goes black so you do not miss the window.
• Format data in recovery. This is a clean flash and it is worth doing properly.
• Sideload the ROM zip from your PC.
• Let it boot. First boot on Android 16 is slow, so leave the phone alone until the setup wizard appears.

Get the order wrong and you end up in a recovery that will not mount anything, which is the single most common way this build goes badly for people.

What works

Google apps behave. Once you sign in during setup, Play Store, Gmail and the rest open and run normally. The Google account restore pulled my apps back without any strange failures, which is not something I can say about every build.

The notification shade and quick tiles are responsive, and the whole system feels quick in a quiet way. Nothing stutters, nothing lags on the home screen. It just moves.

Daily use has been stable. No random reboots, no apps dying in the background, no heat problems while browsing or watching video. For a fresh Android 16 base, that is a solid result.

What is broken or annoying

Two things, and you should weigh both before flashing.

The Play Store shows the device as not certified. Some apps check that, and some of them refuse to run or refuse to show up in search. Most everyday apps do not care. Banking apps often do. That is the part people trip over, and no amount of reinstalling Play Store fixes it, because it is about how the build is signed and registered, not about a setting you missed.

Customization is light. If you like theming, changing system colours, or a ROM that hands you a settings menu full of toggles, this is not it. There is no big theming engine here. Some people will call that plain. Other people will call it the point.

Neither issue is a dealbreaker. But if a bank app is the first thing you open every morning, you want to know about the certification question before you spend an hour flashing.

Who should install it

Install Halcyon OS if you want official, clean, stable Android 16 and you do not care about theming. It is a good pick for someone who wants their Poco X7 Pro to feel like a Pixel without the Pixel price, and who is happy for Google apps to just work.

Skip it if you rely on apps that demand certification, or if a custom-looking home screen is half the reason you flash ROMs. There are builds on this device that scratch that itch much better.

And remember the usual rule for any clean flash on the Poco X7 Pro: your internal storage is going, so move your files off first and note your IMEI. The free Rom Flasher tool on GitHub takes the annoying part of the driver setup off your hands if Device Manager is being difficult.

Full description from the video

Halcyon OS 16 on the Poco X7 Pro — an official Android 16 build, flashed clean, then tested for what works and where it falls short.

Official matters here. It means the build comes from the team rather than a random port, and updates are more likely to keep coming. It flashed without drama using the vendor_boot method and a sideload.

The ROM is clean and close to stock Android 16. The notification shade, quick tiles and Google apps all behave the way you'd expect. If you like your Android without a pile of extra skin, this is your lane.

Two honest notes. The Play Store shows as not certified, which can annoy some apps. And customization is lighter than other ROMs — there's no big theming engine to play with. Neither is a dealbreaker, but you should know before you flash.

📱 Device : POCO X7 Pro (rodin)

🧩 ROM : Halcyon OS 16 (Official)

🤖 Android : 16

🔬 What Was Tested

• First boot, setup and Google account restore
• Notification shade and quick tiles
• Google apps and Play Store certification
• Customization options out of the box
• General daily feel

📊 Verdict

• Clean, stable Android 16 that boots and behaves.
• Official build, so it's a safer bet than a random port.
• Play Store certification is the one thing to plan around.
• Light on customization — great if you want minimal, plain if you want to theme everything.

Common questions

More guides like this