Oppo A9 Custom Rom [hot] -

Unlocking the Full Potential of Your Oppo A9: A Comprehensive Guide to Custom ROMs

The Oppo A9 (2020) was a standout mid-range device upon its release, featuring a Snapdragon 665 chipset and a massive 5,000mAh battery. However, as the device ages, users often find that ColorOS can feel heavy or that official updates have ceased—ColorOS 11 based on Android 11 is the final official stop for many. This is where the world of Custom ROMs comes in, offering a way to breathe new life into your hardware with the latest Android versions and cleaner interfaces. The Realities of Modding an Oppo Device

Before diving into the installation process, it is vital to understand the unique challenges of modding Oppo smartphones.

Locked Bootloaders: Historically, Oppo has made it difficult to unlock bootloaders on global models (typically those starting with "CPH"). Without an unlocked bootloader, you cannot flash a custom recovery or ROM.

MediaTek vs. Snapdragon: The Oppo A9 comes in different variants. While the 2020 version uses Snapdragon, earlier models might use MediaTek Helio P70. Unlocking methods and ROM availability vary significantly between these chipsets. Oppo A9 Custom Rom

Warranty Risks: Unlocking your bootloader and flashing custom software typically voids your manufacturer warranty. Popular Custom ROM Choices for Oppo A9

If you successfully navigate the bootloader hurdle, several custom ROMs are popular in the enthusiast community for providing a superior experience:

I understand you're looking for a guide on custom ROMs for the Oppo A9. However, I need to give you an important heads-up first: Oppo devices (especially A-series) are notoriously difficult to mod due to their locked bootloaders and MediaTek chipsets (MT6765/P35 for the A9).

For most Oppo A9 models (CPH1938, CPH1939, etc.), there is no stable custom ROM available (no LineageOS, Pixel Experience, etc.). Attempting to force one often results in a hard brick. Unlocking the Full Potential of Your Oppo A9:

That said, here is a general guide on what you would need if a ROM existed, plus a realistic alternative.

The Flashing Process

Step 1: Unlock the Bootloader (The Hard Part)

  • Power off your phone.
  • Disconnect battery (if possible) or hold volume buttons while connecting USB to enter BROM mode (preloader).
  • Use mtkclient (GitHub) to run: python mtk da seccfg unlock.
  • This forces the bootloader unlock flag. This step fails on 90% of Oppo A9s due to Secure Boot 2.0.

Step 2: Install a Custom Recovery (TWRP)

  • Unfortunately, there is no official TWRP for Oppo A9.
  • You must boot a "ported" TWRP using fastboot boot twrp.img (find a port on XDA or Hovatek forums). Do not flash it permanently; just boot it.

Step 3: Prepare the GSI

  • Download a arm64 AB GSI from GitHub (e.g., PHHusson’s Treble builds).
  • Extract the .img file.

Step 4: Flash the ROM

  • Reboot to bootloader (adb reboot bootloader).
  • Erase system: fastboot erase system
  • Flash GSI: fastboot flash system your-rom.img
  • Erase user data: fastboot -w (This wipes your internal storage).
  • Reboot: fastboot reboot

Step 5: Post-Installation Fixes

  • The first boot will take 10–15 minutes. Be patient.
  • You will face bugs (e.g., no RIL/calls, broken audio). Install PHH Treble Settings app (available on F-Droid) to fix:
    • Qualcomm → MediaTek audio patch
    • Force VoLTE
    • Alternate battery health

2. crDroid 9 (Android 13) – For Customization Lovers

  • Why choose it: Built on LineageOS, but loaded with features (status bar mods, animations, privacy guard).
  • Status: Stable beta (no major bugs reported).
  • Pros: Deep customization without lag.
  • Cons: OTA updates do not work due to unofficial status.
  • Best for: Tinkerers who love changing fonts, icons, and status icons.

Part 5: Step-by-Step Installation Guide (Oppo A9)

Assuming you have unlocked bootloader and downloaded your chosen ROM (.zip) + GApps (NikGapps recommended).

A. LineageOS (Unofficial)

There is no official LineageOS support for the Oppo A9. Unofficial builds were created by independent developers. The Flashing Process Step 1: Unlock the Bootloader

  • Versions: LineageOS 16 (Android 9), LineageOS 17 (Android 10), and sporadic LineageOS 18 (Android 11) builds.
  • Status: Most builds are "Unofficial" and unmaintained.
  • Bugs: Common issues include broken VoLTE, camera artifacting, and battery drain issues.

The Better Alternative: Stock Mods (No Bootloader Unlock)

Given the risk of bricking your Oppo A9, consider not unlocking the bootloader. Instead, optimize your stock ROM:

  1. De-bloat via ADB: Without root, remove bloatware: 
    adb shell pm uninstall -k --user 0 com.oppo.market
adb shell pm uninstall -k --user 0 com.coloros.safecenter
(etc.)
  2. Install a Launcher: Use Nova Launcher or Lawnchair to hide ColorOS’s ugly UI.
  3. Use Shizuku + Ice Box: Freeze background system apps without root.
  4. Install a Custom Kernel: There is one known kernel named "Derp Kernel for Oppo A9" (XDA) that improves GPU scaling and battery.

3. Kernel and vendor blobs

  • Kernel: Oppo/ColorOS kernel sources should be available per GPL; download official kernel repo matching kernel version (check Oppo open-source portal).
  • Vendor blobs: closed-source firmware for modem, GPU, sensors. Extracting blobs:
    • Use ADB (adb pull) from a running device or dump from OTA/stock firmware.
    • Identify required blobs via build logs (missing symbols) or using device tree and kernel config.
  • Rebuilding kernel:
    • Obtain correct cross-compiler (arm64 toolchain) matching kernel config.
    • Use device kernel defconfig and vendor headers.
    • Apply common patches: upstreaming, CONFIG_* toggles for debug, thermal, CPU governors.

B. Pixel Experience

Unofficial builds of Pixel Experience existed to replicate the Google Pixel UI.

  • Versions: Primarily Android 10 and 11.
  • Status: Discontinued. These ROMs were popular for users wanting a clean UI but suffered from the same hardware driver issues as LineageOS.