The OnePlus Ace series has long occupied a unique position in the smartphone market, offering flagship-level performance at a price point that often undercuts the brand’s primary numbered series. However, as these devices are primarily targeted at the Chinese domestic market, they arrive pre-installed with ColorOS. While ColorOS has evolved into a feature-rich and highly polished interface, it remains distinct from the OxygenOS experience preferred by international users. For many enthusiasts who import the OnePlus Ace 5 Pro (internally known by the model number PKR110), the transition from the regional ColorOS to the global OxygenOS is not merely a preference but a necessity for seamless integration with global services, a bloatware-free environment, and the familiar aesthetic of OnePlus’s international software branch.
The release of OxygenOS 15 and the impending arrival of OxygenOS 16 have intensified interest in this software migration. Transitioning a device from a regional firmware to a global one is a sophisticated process that involves bypassing manufacturer restrictions and utilizing community-developed "Frankenstein" builds. These builds, pioneered by dedicated developers such as XDA Senior Member koaaN, allow users to enjoy the benefits of OxygenOS on hardware that was never officially intended to run it. This guide provides a detailed roadmap for performing this conversion, addressing the technical prerequisites, the flashing procedure, and the critical post-installation fixes required to maintain device functionality.
The Evolution of OxygenOS: Versions 15 and 16
OxygenOS 15, based on Android 15, represents a significant leap forward in terms of system fluidity and intelligent features. It introduces a refined "Parallel Processing" animation engine that ensures the UI remains responsive even under heavy loads. Furthermore, it integrates deeper AI capabilities, such as advanced photo editing and intelligent system resource allocation. For Ace 5 Pro users, moving to this version means gaining access to the Google Play Suite out of the box, improved notification management, and a design language that leans closer to stock Android than its Chinese counterpart.
OxygenOS 16, currently in the testing phase and expected to be released soon, aims to further bridge the gap between hardware and software efficiency. By preparing your Ace 5 Pro now, you position yourself at the forefront of these software advancements. The community-led efforts have already produced several stable builds of OxygenOS 15, including versions 15.0.0.821, 15.0.0.831 (V3), 15.0.0.840, and the most recent 15.0.0.860. These builds are specifically tailored to work with the Ace 5 Pro’s hardware while masquerading as the global OnePlus 13 or similar flagship variants to ensure compatibility.
Essential Prerequisites for Firmware Conversion
Before embarking on the flashing process, it is imperative to understand that this procedure is inherently risky. Modifying system partitions can lead to software instability or, in extreme cases, a bricked device. A comprehensive backup of all personal data—including photos, contacts, and application data—is mandatory, as the conversion requires a complete wipe of the internal storage.
Technical requirements include a Windows-based PC, a high-quality USB data cable, and the necessary ADB and Fastboot drivers installed on the computer. The most critical prerequisite, however, is an unlocked bootloader. OnePlus devices sold in China generally allow for bootloader unlocking, but this step will trigger a factory reset and may affect the device’s warranty status. Users must also ensure their device has at least 60% battery life to prevent an unexpected shutdown during the critical writing phase of the firmware installation.
Navigating the Flashing Procedure
The conversion process utilizes a specialized "Regional Flasher" tool. This tool simplifies the complex task of writing various partition images (such as boot, system, vendor, and product) to the device’s flash memory. Once the desired OxygenOS 15 firmware package is downloaded and extracted on the PC, the device must be booted into Fastboot mode. This is typically achieved by powering off the phone and then holding the Volume Down and Power buttons simultaneously until the Fastboot interface appears.
With the device connected to the PC, the user executes the flashing script provided in the firmware package. This script automates the communication between the computer and the device’s bootloader, systematically replacing the ColorOS partitions with their OxygenOS equivalents. During this time, it is vital not to disturb the USB connection. Once the script completes its execution, the device will typically reboot into the newly installed OxygenOS environment. The first boot may take significantly longer than usual as the system initializes the new file structure and optimizes applications.
Addressing the Signal Connectivity Issue
A common hurdle encountered after converting a Chinese OnePlus Ace 5 Pro to global firmware is the loss of cellular signal. This occurs due to discrepancies in the modem configuration and regional network tuning between ColorOS and OxygenOS. Because the OxygenOS firmware expects certain hardware identifiers and configurations found in global models, it fails to properly initialize the radio on the Chinese hardware.
Fortunately, the developer community has authored a "signal-fix" module to resolve this. To apply this fix, the device must first be rooted. Users have several options for gaining root access, including Magisk, KernelSU, or the newer APatch method. Each offers a different approach to modifying the boot image to allow superuser permissions. Once rooted, the user can flash the specific signal-fix ZIP module through their chosen root manager. After a subsequent restart, the device should successfully register on local cellular networks, restoring full 4G and 5G functionality.
The Bootloader and Security Implications
One of the most frequent questions regarding this conversion is whether the bootloader can be relocked once OxygenOS is installed. The answer is a definitive no. Relocking the bootloader on a device running firmware that does not match its original regional hardware (a "cross-flash") will result in a "verified boot" failure. This triggers a security mechanism that prevents the device from booting, effectively bricking it until the bootloader is unlocked again or the original firmware is restored.
Operating with an unlocked bootloader has implications for system security and certain application functionalities. Features like Google Pay (Wallet) and high-definition streaming on platforms like Netflix (Widevine L1) may require additional workarounds, such as Play Integrity Fix modules, to function correctly. Users must weigh the benefits of OxygenOS against the necessity of maintaining an unlocked bootloader.
Reverting to ColorOS: The Safety Net
Should a user decide that OxygenOS is not suitable for their needs, or if they need to return the device for service, the process can be reversed. Reverting to ColorOS is also the only safe way to relock the bootloader. The community provides stock ColorOS regional flashers, such as versions 15.0.0.821 and 15.0.0.840, which follow a similar flashing logic to the OxygenOS migration.
To go back, the user must again use a PC to flash the official ColorOS images. This will once again wipe all data from the device. After the stock Chinese firmware is successfully restored and the device has been verified to boot correctly, the user can then use Fastboot commands to relock the bootloader, returning the device to its "out-of-the-box" software state.
Conclusion
The ability to flash OxygenOS 15 and 16 onto the OnePlus Ace 5 Pro exemplifies the vibrant spirit of the Android modding community. By leveraging the work of developers like koaaN, users can bypass regional software limitations and unlock the full potential of their hardware with a cleaner, more globally-oriented interface. While the process requires technical diligence—particularly regarding the signal fix and the permanent unlocking of the bootloader—the result is a device that offers the best of both worlds: high-end Chinese hardware specifications paired with the streamlined OxygenOS software experience. As OxygenOS 16 nears its public release, the Ace 5 Pro remains one of the most versatile devices for those willing to venture beyond the factory-installed software.