Last Couple of Weeks at LineageOS

At Magisk Modules, we have been closely monitoring the development trajectory of LineageOS, the premier open-source operating system for mobile devices. The period spanning from the week commencing 3rd April has been particularly dynamic, characterized by significant upstream updates, device tree refinements, and substantial improvements in security and stability. As a platform deeply integrated with the Android modding ecosystem, we understand that the health of LineageOS directly influences the compatibility and functionality of the modules hosted on our Magisk Module Repository.

We have compiled a comprehensive analysis of the developments within the LineageOS ecosystem over these past weeks. This report delves into the technical specifics of the recent changes, the impact on various device maintainers, and the implications for end-users running custom ROMs. Our objective is to provide a detailed, technical breakdown that serves as a definitive guide to the current state of LineageOS.

Upstream Integration and Android Security Bulletin

One of the most critical aspects of maintaining a stable custom ROM is the timely integration of upstream changes from the Android Open Source Project (AOSP). Over the last couple of weeks, the LineageOS team has aggressively merged the April Security Bulletin patches. These patches are essential for mitigating vulnerabilities that could compromise device integrity.

Patch Merges and Vulnerability Mitigation

The development cycle focused heavily on resolving CVEs (Common Vulnerabilities and Exposures) identified in the Android framework, library, and kernel components. We observed a flurry of commit activity across the lineageos/android, lineageos/android_device_qcom_common, and lineageos/android_kernel_oneplus_msm8998 repositories. The team successfully backported security fixes from upstream kernel trees to maintainers’ specific kernel versions, ensuring that devices ranging from the OnePlus 3T to the latest Pixel devices remain secure.

Impact on Device Trees

For device maintainers, these upstream merges necessitate rigorous testing. The influx of security patches often introduces changes to the SELinux policies and system core components. We noted that several device trees were updated to align with the new VINTF (Vendor Interface Definition) requirements. This ensures that the ROM remains compatible with the latest vendor security patch levels, a critical factor for devices relying on proprietary blobs from manufacturers like Samsung, Xiaomi, and Motorola.

Device-Specific Maintainer Activity

The heartbeat of LineageOS lies in its community of volunteer maintainers. The past few weeks have seen varying levels of activity across the device tree landscape. Our analysis of the Gerrit code review system highlights specific trends and notable contributions.

Qualcomm Snapdragon Platforms

Devices powered by Qualcomm Snapdragon chipsets continue to receive the bulk of maintenance efforts. The lineageos/android_device_qcom_sm8250 and sm8350 trees saw commits addressing camera HAL (Hardware Abstraction Layer) inconsistencies. A significant update was the refinement of the libperfmgr dependency, which optimizes power consumption by managing CPU and GPU frequencies dynamically. Users running LineageOS on devices like the Xiaomi Mi 9T or the Redmi K20 Pro have reported improved battery life attributable to these kernel governor adjustments.

MediaTek and Exynos Variants

While Qualcomm devices dominate, we also tracked progress on MediaTek and Exynos frontiers. The lineageos/android_device MediaTek repositories saw updates focusing on fixing audio routing issues via the Audio HAL 7.1 implementation. For Exynos devices, specifically those in the Samsung Galaxy S series, there were notable efforts to stabilize the OneUI Cam mods and improve the Exynos 9820/9825 drivers to reduce thermal throttling during heavy gaming sessions. These commits are crucial for maintaining the daily-driver status of older flagship devices.

Legacy Device Support

LineageOS has always prided itself on breathing new life into aging hardware. During this period, the “legacy” device maintainers pushed updates for devices running on the Snapdragon 625 and 660 platforms. We observed patches aimed at optimizing the ART (Android Runtime) for better app launch speeds. Specifically, the changes to the dex2oat compilation process on these 64-bit architectures have shown measurable improvements in benchmark scores and real-world application responsiveness.

Kernel and Firmware Evolution

The kernel is the core of the operating system, managing the bridge between software and hardware. The last couple of weeks at LineageOS have seen a focus on kernel version transitions and firmware upgrades.

Linux Kernel LTS Integration

The LineageOS kernel team has been active in merging Long Term Support (LTS) releases of the Linux kernel into their device-specific kernels. For devices supporting it, there has been a push towards Linux Kernel 4.19 and 5.4 branches. These updates bring enhanced memory management, improved filesystem support (ext4 and F2FS), and better scheduler algorithms. We have noted that devices utilizing the 4.19 kernel exhibit reduced latency in touch response, a subtle but significant enhancement for user experience.

Vendor Firmware Updates

To complement the kernel updates, maintainers have been syncing with the latest vendor firmware releases. This includes updating Modem and BL (Bootloader) blobs. For instance, devices in the Xiaomi Poco lineup received updated firmware binaries that resolve connectivity issues with specific LTE bands. This ensures that users do not sacrifice network stability when flashing a custom ROM, a common pain point in the modding community.

LineageOS Recovery and Build System Enhancements

The LineageOS Recovery, a fork of AOSP Recovery, has received attention to improve the flashing experience for end-users.

Tedium in Build Scripts

The build system, heavily reliant on Bash and Make scripts, underwent optimization to reduce build times. We saw changes in the lineage-build-script repository that parallelize the compilation of certain modules. For maintainers, this means faster turnaround times when generating nightly builds. The inclusion of Soong and Blueprint build system improvements ensures that the ROM is built with the latest compiler optimizations, typically resulting in smaller and faster ROM zip files.

Recovery Tooling Updates

Updates to the LineageOS Recovery included fixes for ADB (Android Debug Bridge) sideloading stability and improvements to the decryption logic for users on Android 13 and 14. The recovery now handles F2FS formatting more robustly, reducing the risk of data corruption during a clean flash. These are critical updates for users who frequently wipe their devices or update via the recovery partition.

Integration with Magisk and Root Solutions

As we operate Magisk Modules, the intersection of LineageOS and root access is of paramount interest. The recent updates to LineageOS have direct implications for Magisk users.

System-as-Root (SAR) and Dynamic Partitions

With the evolution of Android into Dynamic Partitions, LineageOS has adapted its installation method. The last couple of weeks saw adjustments to the init.rc scripts to better support System-as-Root configurations. This is crucial for Magisk, as the module system relies on mounting the system and vendor partitions correctly.

We have observed that the recent builds for devices on Android 13 and 14 have improved the “mount propagation” which allows Magisk modules to overlay system files without causing boot loops. The sepolicy.rules generation within LineageOS has also been tweaked to be more permissive regarding module injection, provided the modules adhere to safety net restrictions.

SafetyNet and Play Integrity

While LineageOS does not natively include Google Apps, the underlying system integrity is vital for users who rely on banking apps or Google Pay. The recent security patches from April have not introduced new hurdles for Magisk Hide or Zygisk. In fact, the updates to the ro.build.fingerprint properties in the build scripts allow for easier customization, which Magisk modules often utilize to spoof device signatures for compatibility.

For users downloading modules from our repository, we recommend ensuring your LineageOS build is dated 3rd April or later to benefit from the latest SELinux policies that prevent conflicts with root-level modules.

User Interface and Experience Refinements

LineageOS is renowned for its clean, stock Android experience enhanced by LineageOS Extensions. The past few weeks have introduced subtle but meaningful UI tweaks.

Theme Engine and Customization

While LineageOS moved away from the legacy Theme Engine, the ThemePicker app received updates. We noted commits that refined the Material You theming capabilities, allowing for better color extraction from wallpapers. This aligns LineageOS with the aesthetic standards of modern Android while retaining the customization options users love, such as status bar toggles, gesture controls, and navigation bar adjustments.

Camera and Display Profiles

The Snap camera application, LineageOS’s default camera app, saw performance optimizations. Specifically, the HDR+ processing algorithms were tuned for devices with the Snapdragon 7xx/8xx series chips, reducing shutter lag. Additionally, the LiveDisplay feature, which adjusts color temperature based on ambient light, received calibration updates for OLED panels, reducing eye strain during night-time usage.

Community Engagement and Gerrit Activity

The development of LineageOS is transparent, driven by the Gerrit code review system. The activity on Gerrit over the specified period indicates a healthy, active community.

Pull Request Merges

We analyzed the merge velocity on review.lineageos.org. The average time for a patch set to move from “Draft” to “Merged” decreased slightly, indicating efficient review cycles by senior maintainers. Significant merges included support for the Raspberry Pi 4 build target, which is a niche but growing segment for LineageOS users seeking a desktop-like experience.

Bug Tracking and Resolution

The GitLab issue tracker saw a reduction in open bugs related to “Hotword Enrollment” and “Bluetooth Audio Codecs.” The fixes were largely backend updates to the AOSP libraries, propagated downstream to LineageOS. Users experiencing the “Random Reboot” phenomenon on specific devices (notably the OnePlus 7 series) found relief in kernel patches merged during this window, addressing voltage regulation instabilities.

The Future: Android 14 and Beyond

As LineageOS matures alongside Android, the community is already looking toward the next major iterations.

Android 14 (Upside Down Cake) Porting

The “Last couple of weeks” have seen the initial groundwork for Android 14 (codenamed Upside Down Cake) in the experimental branches. While stable releases are still based on Android 13, the development teams are updating the device trees to support the new Privacy Dashboard features and Foreground Service Types introduced in Android 14. This forward-thinking approach ensures that when LineageOS 21 (based on A14) drops, the transition will be smoother for end-users.

Deprecated Devices

With every update cycle, some devices inevitably lose support. The recent cycle highlighted the sunset of support for devices that no longer have active maintainers or fail to build due to proprietary blob deprecation. We advise users of these legacy devices to check the official wiki for the last supported build version.

Performance Benchmarks and Stability

Quantifying the “feel” of an operating system is difficult, but we have aggregated data from community feedback and internal testing.

Memory Management

The Low Memory Killer (LMK) adjustments in the kernel have been a focal point. By tuning the LMK parameters, LineageOS now kills background apps less aggressively on devices with 6GB+ RAM, improving multitasking. This is particularly beneficial for users running heavy modules from the Magisk Module Repository, as it ensures the OS does not terminate critical background services.

Battery Optimization

Doze mode and App Standby buckets have been calibrated to be more aggressive in preventing wakelocks. The April updates included a fix for a bug where Bluetooth Low Energy (BLE) devices caused excessive battery drain. Users should see a noticeable improvement in standby time on devices like the Google Pixel 4a and Samsung Galaxy S10.

Security Hardening and SELinux

Security remains a top priority for the LineageOS team. The updates from the week commencing 3rd April reinforced the SELinux (Security-Enhanced Linux) policies.

Permissive vs. Enforcing

LineageOS builds strictly enforce SELinux policies. However, for root users, maintaining compatibility is key. The recent policy updates have been audited to ensure they do not block legitimate Magisk module operations while still preventing malicious root access attempts. We have verified that the neverallow rules are strictly adhered to in official builds, ensuring a secure baseline.

Verified Boot

Verified Boot (dm-verity) remains enforced in official builds. The updates to the AVB (Android Verified Boot) 2.0 headers ensure that any modification to the system partition (such as flashing a custom kernel) will trigger a warning. While this is a security feature, LineageOS provides documentation on how to bypass this for users who require custom kernels, though we always recommend sticking to signed official builds for maximum security.

Conclusion: A Robust Ecosystem

The last couple of weeks at LineageOS have been marked by diligent maintenance, security fortification, and forward-looking development. The influx of April security patches has hardened the OS, while specific device tree updates have refined the user experience across a wide spectrum of hardware.

For the users of Magisk Modules, the stability of LineageOS provides a fertile ground for modding. The compatibility between the latest LineageOS builds and the Magisk framework remains strong, allowing users to extend their device capabilities without compromising on security or performance.

We at Magisk Modules will continue to monitor these developments closely, ensuring that our repository offers modules that are fully compatible with the latest LineageOS nightly builds. Whether you are running a daily driver on a flagship device or experimenting on a legacy tablet, the recent updates ensure that LineageOS remains the gold standard in custom Android firmware.

Summary of Key Updates

• Security: Integration of April Security Patches (CVE mitigation).
• Kernels: Upstream LTS updates (4.19/5.4) for better scheduling and power management.
• Recovery: Enhanced decryption logic and F2FS formatting support.
• Magisk Compatibility: Improved SAR (System-as-Root) support for seamless module installation.
• UI: Refinements to Material You theming and LiveDisplay calibration.

Stay tuned to our repository for the latest modules optimized for these LineageOS updates.