The pursuit of the latest software innovations often comes with a hidden cost, a reality currently being faced by early adopters of the Xiaomi 14 Ultra and the newly released Xiaomi 15 Ultra. As the mobile industry begins its transition toward the Android 16 ecosystem via the HyperOS 3 framework, a significant technical hurdle has emerged that threatens the core usability of Xiaomi’s most premium hardware. Reports from the enthusiast community, specifically those utilizing the popular Xiaomi.eu custom ROM distributions, indicate a severe regression in battery efficiency. This phenomenon is not merely a minor software bug but appears to be a systemic failure in how the latest operating system interacts with the underlying silicon, leading to unprecedented levels of idle power consumption that effectively prevent the devices from entering their intended low-power states.
The situation first came to light through rigorous testing conducted by members of the Xiaomi.eu community, a group known for porting and optimizing Chinese firmware for global audiences. According to detailed telemetry data, affected Xiaomi 14 Ultra and 15 Ultra units are experiencing an idle battery drain of approximately -1.15W. In more practical terms for the end-user, this translates to a loss of 2.6% to 3% of total battery capacity every hour while the device is supposedly inactive. For a flagship smartphone equipped with a high-capacity battery, such a drain rate is catastrophic; it implies that a device sitting untouched on a nightstand could lose nearly a third of its charge over a standard eight-hour sleep cycle. This level of power draw is typically associated with active screen-on usage or high-background processing, not a device in standby mode.
The investigative groundwork for identifying this issue was laid by a prominent forum analyst known as bear0610. Through a forensic examination of system logs and kernel behavior, this investigation revealed that the culprit is not a rogue third-party application or a simple sync error. Instead, the problem resides deep within the architectural layers of the operating system—specifically at the Hardware Abstraction Layer (HAL) and the System Linker level. The findings suggest that the system is trapped in a series of "infinite error loops." In computing, an infinite loop occurs when a sequence of instructions lacks a functional exit condition, causing the processor to execute the same task repeatedly. In this specific instance, the loops are occurring as the software attempts to communicate with the hardware, failing, and then immediately retrying the operation without pause.
To understand the gravity of this issue, one must look at the role of the Hardware Abstraction Layer. The HAL serves as a critical bridge between the generic Android framework and the specific hardware drivers provided by the manufacturer. When a user updates to a major new version of Android, such as the jump to Android 16, the framework expects the HAL to provide specific responses and data formats. If there is a mismatch, the system cannot correctly initialize or manage the hardware components. According to the data provided by bear0610, the current "Vendor Blobs"—the proprietary, closed-source files provided by Xiaomi and its component suppliers—appear to be fundamentally incompatible with the Android 16 system framework currently being utilized in the HyperOS 3 builds.
This incompatibility manifests as a constant stream of hardware interrupts. In a healthy system, the System on a Chip (SoC) should enter a "Deep Sleep" state when the screen is off and no high-priority tasks are running. In this state, the CPU cores are essentially powered down, and power consumption drops to negligible levels. However, because the HAL is stuck in an infinite loop of retries and error reporting, the SoC is forced to remain in an active state. The processor is essentially "kept awake" by the constant noise of driver-level failures, meaning the power-saving benefits of modern silicon architecture are completely bypassed.
The investigation further distinguished between the two affected models, showing that while both suffer from the same fundamental battery drain, the Xiaomi 15 Ultra faces an even more complex set of challenges. While the 14 Ultra is primarily struggling with identical HAL loops, the 15 Ultra build is reportedly compromised by "Linker symbol mismatches." The System Linker is responsible for connecting different pieces of code together during execution. When a symbol mismatch occurs, it means the operating system is looking for a specific function or piece of data within a library that either does not exist or has been moved. This results in further instability and contributes to the overall inability of the system to reach a stable, low-power equilibrium.
Interestingly, the researcher noted that these issues were observed on non-rooted devices running the Xiaomi.eu ROM, suggesting that the problem is baked into the ROM’s core integration of the Android 16 base rather than being a byproduct of user-level modifications. Furthermore, a common troubleshooting step—executing the "stop logd" command to halt the system logger—proved ineffective in solving the power crisis. While stopping the logger successfully hid the error messages from the view of developers, it did absolutely nothing to reduce the actual wattage being pulled from the battery. This confirms that the drain is a physical consequence of hardware-level activity (the constant retries and interrupts) rather than just the overhead of writing error logs to the disk.
To validate the theory that this is a regression specific to the Android 16 adaptation, the same tests were performed on builds based on Android 15. Under the previous OS version, the Xiaomi 14 Ultra and 15 Ultra exhibited normal power behavior, with the SoC successfully entering Deep Sleep and idle drain remaining within acceptable industry standards. This side-by-side comparison provides a clear "smoking gun," pointing toward the transition to Android 16 and the accompanying HyperOS 3 changes as the sole cause of the current inefficiency. It suggests that the integration of the new Android version has outpaced the development of stable, compatible vendor drivers.
The broader implications for Xiaomi are significant. The "Ultra" line represents the pinnacle of the brand’s engineering, often marketed to power users and professionals who demand the highest reliability. While the issues currently documented are largely confined to the Xiaomi.eu community—which often acts as a precursor to wider releases—it serves as a warning for the official Global and Chinese stable releases of HyperOS 3. If these HAL and Linker issues are not resolved before the software reaches a wider audience, the company could face a PR crisis regarding the longevity and thermal performance of its flagship devices. High idle drain not only inconveniences the user but also generates heat and accelerates the chemical degradation of the battery cell over time.
For the time being, the tech community is treating these findings as a localized but highly credible warning. While the work done by bear0610 is being hailed for its technical depth and clarity, the issue has not yet reached a critical mass of reports from the general public. This is partly due to the niche nature of the early Android 16 builds and the specific demographic that installs custom ROMs. However, as Xiaomi ramps up its internal testing and begins pushing more developer previews, the spotlight on these "Vendor Blob" incompatibilities is expected to intensify.
For users currently operating a Xiaomi 14 or 15 Ultra, the advice from technical circles is one of caution. Those who rely on their devices for daily productivity are encouraged to remain on stable Android 15-based firmware until there is official confirmation that the HAL loops have been patched. The transition to a new Android version is notoriously difficult for manufacturers, as it requires a delicate synchronization between Google’s source code, the manufacturer’s custom skin, and the silicon vendor’s proprietary drivers. In this instance, it appears the synchronization has failed, leaving the hardware and software in a state of perpetual conflict.
As this story develops, the focus will shift to how quickly the development teams can update the necessary system libraries to align with the Android 16 framework. The resolution will likely require new binary blobs from the chipset manufacturers and a comprehensive rewrite of how HyperOS 3 handles system-level interrupts. Until such an update is deployed, the "Ultra" experience remains hampered by a fundamental flaw that turns these high-performance machines into power-hungry liabilities when they should be at their most efficient. The community continues to monitor the situation closely, waiting for the next iteration of the ROM to see if the infinite loops can finally be broken.