Have an old Lenovo M8 Gen 2 HD Tablet, what OS should I flash on it?

We understand the predicament you are facing with your Lenovo Tab M8 (Gen 2) HD. When a device reaches the end of its official software support lifecycle, it often feels obsolete, sluggish, and limited by an aging Android version. However, with the right approach to custom firmware, we can breathe new life into this capable hardware. The Lenovo Tab M8 (Gen 2), codenamed TB-8505X (for the Wi-Fi model) or TB-8505F (for the LTE model), features a MediaTek Helio P22T (MT8768T) processor, 2GB or 3GB of RAM, and 16GB/32GB of eMMC storage. While these specifications were entry-level in 2020, they are still perfectly usable for media consumption, light browsing, and reading, provided we strip away the bloatware and optimize the system.

The core question is not just “what OS,” but rather, what is the balance between performance, stability, and features? We must navigate the landscape of Custom ROMs, Android Open Source Project (AOSP) builds, and GSI (Generic System Image) implementations. Because Lenovo is relatively conservative with kernel source releases and bootloader unlocking, the Lenovo Tab M8 (Gen 2) community is smaller than that of Xiaomi or OnePlus devices. This makes choosing the right path critical to avoid bricking the device or losing essential hardware functionality.

In this comprehensive guide, we will analyze the best operating system options available for your Lenovo M8 Gen 2, covering the prerequisites, installation methodologies, and the specific pros and cons of each OS variant. Our goal is to empower you to make an informed decision that transforms your tablet from a neglected gadget into a snappy, personalized Android device.

Understanding the Hardware Constraints and Bootloader Unlocking

Before we discuss specific operating systems, we must address the foundational barrier for the Lenovo Tab M8 (Gen 2): Bootloader Unlocking. Unlike many Xiaomi or Motorola devices, Lenovo does not provide a straightforward, user-friendly method to unlock the bootloader for this specific model.

The Bootloader Hurdle

The Bootloader is the first program that runs when you power on your tablet. It checks the digital signature of the kernel and system before loading them. For security, manufacturers lock it to prevent unauthorized modifications. To flash a custom OS, we must unlock this bootloader.

For the Lenovo Tab M8 (Gen 2), the standard method involves:

Enabling OEM Unlocking in Developer Options.
Obtaining an unlock token from Lenovo (which is often discontinued or unresponsive for older budget tablets).
Using ADB and Fastboot commands to unlock the device.

If you cannot unlock the bootloader via official means, your options are severely limited to Rooting via Magisk (using a patching method) or attempting to exploit vulnerabilities like EDL (Emergency Download Mode). However, for the purpose of this guide, we assume you have either successfully unlocked the bootloader or are willing to explore Root-based optimizations and GSI flashing if the bootloader permits.

The Architecture: arm64 and Treble

The Helio P22T is an ARM64 processor. Fortunately, this tablet supports Project Treble, which means it comes with a vendor partition that supports generic system images. This is a massive advantage. Even if dedicated custom ROMs are scarce, we can often flash Android GSI builds (Generic System Images) provided by the PHH-Treble project or others. This opens the door to newer Android versions like Android 12, 13, and 14, despite Lenovo only officially supporting up to Android 10 or 11.

Option 1: Stock ROM Optimization (The Safe Route)

If you are hesitant to risk bricking your device or losing access to proprietary Lenovo features (like aggressive battery optimization), we recommend optimizing the existing Stock Android ROM. This approach focuses on debloating and rooting rather than replacing the entire OS.

Debloating and Performance Tweaks

The stock Lenovo firmware comes with significant bloatware (Netflix, McAfee, social media preloads) that consumes the limited 2GB/3GB RAM. We can use ADB Debloater tools to remove these system apps without root. This frees up storage and reduces background processes, making the UI significantly snappier.

Rooting with Magisk

We highly recommend rooting the device with Magisk. Since the Lenovo Tab M8 (Gen 2) utilizes a MediaTek chipset, rooting opens the door to Modules that optimize the kernel and memory management.

Magisk Modules found on the Magisk Module Repository (https://magiskmodule.gitlab.io/magisk-modules-repo/) can be instrumental. Modules like “Lite GApps” or “Systemless Hosts” can further streamline the system.
Kernel Adiutor (root required) allows us to tweak the CPU governor (switching from schedutil to performance or interactive) to reduce lag on the Helio P22T.

Option 2: Android GSI (Generic System Image)

If you want a newer version of Android than what Lenovo provides, Project Treble GSI is the most viable solution for the Lenovo Tab M8 (Gen 2). A GSI is a pure Android build that runs on top of the existing vendor partition.

Why GSI?

Official custom ROMs for budget tablets are rare. GSI builds allow us to run Android 12, 13, or 14 on devices that never received those updates officially. For the TB-8505X, GSI compatibility is generally good, but not perfect.

Recommended GSI Builds

PHA (Phhusson) AOSP GSI:
- This is the gold standard for Treble compatibility. We recommend looking for the arm64-ab variant (Android 12 or 13). The Helio P22T handles Android 12 reasonably well, but Android 13 might be heavy for 2GB RAM models.
- Pros: Close to stock Android, frequent updates, active community support.
- Cons: Requires manual installation via Fastboot, potential bugs with camera or audio codecs.
Crdroid or LineageOS GSI:
- Some developers port LineageOS to GSI formats. These usually offer a smoother experience than raw AOSP due to custom optimizations.
- Pros: Privacy guard, customization options, lighter than stock.

Installation Process for GSI

To flash a GSI, you generally follow this workflow:

Unlock Bootloader: Essential.
Disable Verity/Verification: Use Fastboot to flash vbmeta.img with the flag --disable-verity --disable-verification.
Format Data: You must format the data partition (not just wipe) to remove encryption.

Flash GSI Image:

fastboot erase system
fastboot flash system system.img

Reboot: The first boot will take longer (Dalvik/Cache rebuild).

Warning: If your tablet is the HD (1280x800) variant, ensure the GSI supports low-resolution displays. Some GSIs are optimized for FHD+ and may stretch the UI incorrectly on the M8’s lower resolution.

Option 3: Gaming-Optimized Kernels (Lite OS Approach)

Since the Helio P22T is an entry-level chip, a heavy OS like a full GSI might feel sluggish. We can adopt a “Lite OS” philosophy by modifying the kernel and system properties.

Custom Kernel Development

While there are few fully compiled custom kernels for the Lenovo Tab M8 (Gen 2), we can modify the stock kernel via Magisk. We can apply ZRAM (Virtual RAM) adjustments to mitigate the 2GB RAM limitation.

ZRAM Size Adjustment: Increasing ZRAM to 1GB or 1.5GB helps keep more apps in memory.
CPU Throttling: The Helio P22T can throttle aggressively to prevent overheating. Using a custom kernel configuration, we can set higher temperature limits to maintain performance during longer sessions.

MicroG vs. GApps

When flashing a custom OS, we must decide on Google Services.

Stock GApps (OpenGApps): Heavy. They consume background RAM and battery.
MicroG: A free re-implementation of Google Play Services. It is significantly lighter and better for privacy. On a 2GB RAM tablet, MicroG is the superior choice for stability.
NikGApps Core: If you need the Play Store, use the “Core” package only to minimize footprint.

Option 4: Linux on ARM (The Power User Route)

For users who want to repurpose the tablet as a lightweight Linux device, PostmarketOS or Ubuntu Touch are experimental options.

PostmarketOS

PostmarketOS brings a true Linux distribution to mobile devices. The MediaTek Helio P22T is supported by the mainline kernel branch in some capacity, but support for the Lenovo M8 (Gen 2) specifically is still in the “community” or “testing” phase.

Use Case: Ideal if you want to use the tablet as a terminal, a lightweight web browser, or for coding (VS Code runs via web or native builds).
Hardware Support: Wi-Fi and touchscreen usually work first; Bluetooth, GPS, and camera often lag behind in development.

Terux (Android x86 Port)

While primarily for Intel/AMD hardware, there are attempts to port Android x86 to ARM devices via emulation or specific builds. This is generally not recommended for the Lenovo M8 due to performance overhead and compatibility issues with the ARMv8 architecture.

Detailed Comparison: Which OS Should You Choose?

We have broken down the decision matrix based on your usage profile and technical expertise.

Operating System	Best For	Difficulty	Performance	Stability
Stock ROM (Rooted)	Media, Reading, Stability	Low	Moderate	High
Android GSI (A12/13)	Modern UI, New Features	Medium	Moderate to Low	Medium
Linux (PostmarketOS)	Productivity, Development	High	Low (App dependent)	Low
Gaming Mod (Lite)	Emulation, Light Gaming	Medium	High	Medium

Scenario A: The Casual User

If you use the tablet for Netflix, YouTube, and Web Browsing, stick to Stock ROM. Root it using Magisk and apply a Debloater Script. Install a lightweight browser like Via Browser or Firefox Lite. Do not flash a GSI; the 2GB RAM will struggle with modern Android background management.

Scenario B: The Tinkerer

If you enjoy flashing and want a cleaner interface, flash a Android 11 or 12 GSI (PHA Project). You will get newer security patches and a modern look. However, be prepared to troubleshoot SELinux denials or camera glitches. Use the Magisk Module Repository to patch any missing functionality.

Scenario C: The Privacy Advocate

Flash a de-Googled AOSP GSI and install MicroG (if you need some sync) or avoid Google entirely. Use F-Droid for open-source applications. This drastically reduces background battery drain and improves system responsiveness on the Helio P22T.

Technical Deep Dive: Handling the MediaTek Chipset

The MediaTek Helio P22T (MT8768T) is a capable chip, but it requires specific handling when flashing custom OS.

Project Mainline

Android 12 and higher utilize Project Mainline, which updates core OS components via the Play Store. While this is great for security, it adds overhead. On the M8 Gen 2, we recommend disabling unnecessary Mainline modules (like the Connectivity Module if you rely on custom kernels) to save space on the system partition.

Vulkan and OpenGL ES

The PowerVR GE8320 GPU supports Vulkan 1.1. When selecting a custom kernel or GSI, ensure that Vulkan drivers are intact. If you experience graphical glitches in games or launchers, you may need to flash a specific vendor package (vndk) to restore compatibility.

Vendor Partition Integrity

The most critical mistake users make is wiping the Vendor partition. On the Lenovo M8 (Gen 2), the vendor partition contains the calibration data for the screen, sensors, and modem. If you flash a GSI that requires a wiped vendor, you must have a backup of your original vendor partition. Without it, you will lose Wi-Fi calibration and touch sensitivity.

Installation Prerequisites and Tools

We recommend gathering the following tools before attempting any OS flash.

ADB and Fastboot Platform Tools: Essential for communicating with the device in bootloader mode.
USB Drivers: MediaTek VCOM drivers for Windows, or generic ADB drivers.
Custom Recovery (Optional but Recommended):
- For the Lenovo M8 Gen 2, a port of TWRP (Team Win Recovery Project) or OrangeFox Recovery is necessary if you intend to flash zips via SD card.
- Note: Some recoveries struggle with decryption. You may need to format data to F2FS or EXT4 to bypass encryption issues.
Firmware Images:
- Stock ROM: Keep a copy of the official stock ROM (TF-OS) on your PC. This is your safety net.
- GSI Image: Download the latest .img file.
- vbmeta.img: Required to disable verification.

Troubleshooting Common Issues

Even with the best preparation, issues can arise. Here is how we address the most common problems on the Lenovo Tab M8 (Gen 2).

Bootloop after Flashing GSI

If the device gets stuck on the Lenovo logo or the Android animation endlessly:

Cause: The vendor image is incompatible with the system image.
Solution: Reboot to Fastboot and flash the stock system.img back. Alternatively, try a different GSI variant (e.g., switch from ab to vndklite).

Stuck in Fastboot Mode

If the tablet boots directly to the “Fastboot” screen:

Cause: Bootloader unlocked successfully, but the boot image is corrupted.
Solution: Flash the stock boot.img or logo.bin.

No Wi-Fi or Bluetooth

This is common with GSIs. The drivers for the MediaTek chip (MT6625L or similar) are not included in the generic system image.

Solution: You need to extract the firmware files from your stock ROM (persist.img, nvram.img) and flash them via Fastboot or TWRP. Do not wipe persist!

Final Recommendation

After analyzing the hardware capabilities and the software ecosystem for the Lenovo Tab M8 (Gen 2), we propose the following definitive path:

For the vast majority of users, the “Stock ROM (Rooted + Debloated)” is the superior choice. The hardware limitations (2GB RAM, eMMC storage) are too significant to run modern Android versions (13/14) smoothly. A GSI will result in frequent app reloading and UI stuttering.

However, if you have the 3GB RAM model and possess technical patience, flashing a Android 12 GSI (PHA) via Fastboot will provide a modern security patch level and a cleaner interface.

Step-by-Step Summary (Stock Optimization)

Backup all data.
Install Magisk by patching the stock boot.img (extracted from the firmware).
Boot into Magisk and install modules from the Magisk Module Repository:
- Systemless Hosts Module (for ad blocking).
- Swap Disabler / ZRAM Tweak (to optimize memory).
Use a debloater tool to remove system apps (Netflix, McAfee, etc.).
Enable Force GPU Rendering in Developer Options to offload UI drawing.

Step-by-Step Summary (GSI Flashing)

Unlock Bootloader (if possible).
Download a Treble-compatible GSI (Android 11 or 12 recommended).
Disable verity: fastboot flash vbmeta vbmeta.img --disable-verity --disable-verification.
Format Data: fastboot format userdata.
Flash System: fastboot flash system system.img.
Reboot and wait for first boot (up to 15 minutes).

By following this guide, we ensure that your Lenovo Tab M8 (Gen 2) is not relegated to the drawer of obsolete electronics. Whether through the stability of a rooted stock ROM or the novelty of a generic system image, we can maximize the utility of your device. Always remember to check the specific codename (TB-8505X) before downloading any firmware to ensure compatibility.

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