Thanks to the low price of POCO’s first flagship device and official support from POCO, the POCO F1 is poised to become incredibly popular on the XDA forums. Just a few weeks ago, a few Android 8.1 Oreo-based custom ROMs popped up on our forums for the device. Later, the first Android Pie custom ROM became available for the device. For those of you who don’t want to wait for more device-specific, Android Pie-based custom ROMs and want to try one of the existing Generic System Images (GSIs), you should check out this modified vendor and boot image by XDA Senior Member shahan_mik3.
For those of you are aren’t aware, every device launching with Android 8.0 Oreo and above supports Project Treble. Project Treble involves separating the Android framework from the vendor HALs, so the Android OS and the files that make your phone’s hardware function are kept separate. Instead, the vendor interface provides a way for the vendor implementation to communicate with the OS. The goal is to make it possible for Android OS upgrades to occur independently of vendor file updates, and as a consequence, makes it possible for Treble-enabled devices to boot a pure AOSP ROM—the GSI. The Treble specification was refined with Android 8.1 Oreo and mostly finalized Android 9 Pie, so most devices launching with pre-Android Pie software will still have a few bugs when flashing a GSI that can only be fixed via modification of the vendor implementation.
That’s exactly the purpose of shahan_mik3’s modified vendor and boot image. Currently, if you flash any Android Pie GSI on top of the vendor and boot images that ship on the Xiaomi POCO F1, you’ll have issues with VoLTE as well as a few other things. However, if you flash this modified vendor image, you can then flash any Android Pie GSI without VoLTE bugs. The developer states that additional fixes will be added to their modified vendor and boot image in the future.
How to install modified vendor and boot image for POCO F1
Go to this thread and download the latest modified vendor and boot image provided by the developer. We also recommend you read the first few posts thoroughly. Assuming you already have an unlocked bootloader, you just fire up TWRP (the developer recommends the one by XDA Recognized Developer TheStrix as linked here), format the user data partition (if MIUI was previously installed and the device is encrypted), and then flash the modified vendor and boot image zip package.
After flashing the zip package, you can then go to our Project Treble device development forum and download any A-only Android Pie GSI of your choice. The POCO F1 is an A-only device (meaning, it does not have A/B partitions for seamless updates), so you cannot flash any GSIs that were built for A/B devices. Also, the POCO F1 is an ARM64 device by nature of the Qualcomm Snapdragon 845 system-on-chip, so you cannot flash any GSIs built for ARM devices. Lastly, if you ever plan on flashing a non-GSI ROM or MIUI, you will need to re-flash the stock vendor image. Otherwise, you’ll probably encounter some bugs.
Download modified vendor image for POCO F1
Join the Xiaomi POCO F1 forum on XDA
Join the Project Treble forum on XDA
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