Q1. Which AX5 firmware build is best for general repairs?

A.15 is the most practical starting point for CPH1851EX repairs, since later builds are commonly used to resolve hang-on-logo and stability issues compared to early releases.

Q2. What does “CPH1851EX” mean in these filenames?

Firmware collections for OPPO AX5 often publish EX-branch packages labeled CPH1851EX, and flashing should match the phone’s software branch to avoid incompatibilities.

Q3. Can these packages fix “stuck on OPPO logo” problems?

Yes—AX5 flash-file guides specifically reference using these stock ROM packages to fix hang-on-logo/bootloop behavior.

Q4. Is MSM Download Tool the correct flashing method for OPPO AX5?

MSM Download Tool is widely described as an after-sales firmware flashing utility for OPPO/Realme devices and is commonly shown being used for AX5 CPH1851 flashing.

Q5. Should A.01/A.04/A.05 be flashed on a phone currently running a newer build?

Early builds are typically downgrade targets only for specific service workflows; unnecessary downgrades increase risk and are not recommended when a newer stable build is available.

Q6. What Android version does OPPO AX5 typically run on these builds?

OPPO AX5 CPH1851 is widely listed as Android 8.1 with ColorOS 5.1.

Q7. What is the most common flashing mistake that causes failure?

The most common failure point is mismatching the model/branch (CPH1851 vs other OPPO models) or using an incompatible package, which is frequently highlighted in repair-focused flash-file pages.

OPPO AX5 CPH1851EX Firmware A.01–A.15 Stock ROM Download

OPPO AX5 (model CPH1851) is an entry-level Snapdragon device commonly used for everyday apps, but over time many units develop slowdowns, random freezes, and “stuck on logo” boot issues after failed updates or storage pressure. The firmware builds on this page are full stock packages designed to restore a clean system state, fix bootloops/lock issues, and return stability when normal OTA updates or factory resets are not enough.

Download Firmware for OPPO AX5 (CPH1851 / CPH1851EX)

Builds are listed from newest to oldest. Newer builds (A.12–A.15) are generally preferred for better stability, while older builds (A.01–A.07) are mainly useful for downgrade-compatible service work or specific troubleshooting scenarios.

Filename	Region / Variant	Build Number	Build Date	Android Version	Flashing Method	Notes	File Size	Download
CPH1851EX_11_A.15_191230_5c53d686.7z	EX (CPH1851EX)	CPH1851EX_11_A.15	2019-12-30	Android 8.1 / ColorOS	MSM Download Tool (Qualcomm service flash)	Recommended “latest” baseline for most repairs on CPH1851EX; commonly used to fix bootloop, hang-on-logo, and stability issues after bad updates.	3.47 GB	Download From MediaFire
CPH1851EX_11_A.12_190925_fd1e2a2d.zip	EX (CPH1851EX)	CPH1851EX_11_A.12	2019-09-25	Android 8.1 / ColorOS	MSM Download Tool (Qualcomm service flash)	Well-known “repair” build referenced in flash-file collections for fixing hang-on-logo problems and removing screen locks on AX5.	3.9 GB	Download From MediaFire
CPH1851EX_11_A.11_190716_f63a448a.rar	EX (CPH1851EX)	CPH1851EX_11_A.11	2019-07-16	Android 8.1 / ColorOS	MSM Download Tool (Qualcomm service flash)	Older stable build for rollback/testing; still commonly used for recovery when newer packages fail to validate due to tool/driver mismatches.	3.8 GB	Download From Google Drive
Oppo_AX5_CPH1851_EX_11_A.07_190128.zip	EX (CPH1851EX)	CPH1851EX_11_A.07	2019-01-28	Android 8.1 / ColorOS	MSM Download Tool (Qualcomm service flash)	Older build; use only when a controlled downgrade is required for diagnostics or compatibility.	4.52 GB	Download From Google Drive
CPH1851EX_11_A.07_190128_e3b3014e.rar	EX (CPH1851EX)	CPH1851EX_11_A.07	2019-01-28	Android 8.1 / ColorOS	MSM Download Tool (Qualcomm service flash)	Same build as A.07 above in an alternate archive format; avoid flashing A.07 if already on later builds unless a downgrade path is confirmed safe.	4.01 GB	Download From Google Drive
CPH1851EX_11_A.05_181109_77ab15fa.rar	EX (CPH1851EX)	CPH1851EX_11_A.05	2018-11-09	Android 8.1 / ColorOS	MSM Download Tool (Qualcomm service flash)	Early build; mainly useful for repair workflows on devices that shipped on very early EX firmware.	3.95 GB	Download From Google Drive
CPH1851EX_11_A.04_180924_77ab15fa.rar	EX (CPH1851EX)	CPH1851EX_11_A.04	2018-09-24	Android 8.1 / ColorOS	MSM Download Tool (Qualcomm service flash)	One of the earliest EX packages; intended for very specific rollback/repair cases only.	3.93 GB	Download From Google Drive
Oppo_AX5_CPH1851_EX_11_A.01_180816.zip	EX (CPH1851EX)	CPH1851EX_11_A.01	2018-08-16	Android 8.1 / ColorOS	MSM Download Tool (Qualcomm service flash)	Oldest build: first-wave EX firmware; avoid flashing unless a service-level downgrade is required and fully supported.	4.37 GB	Download From Google Drive

Clarity notes: OPPO AX5 is widely identified as CPH1851 with Snapdragon 450 and Android 8.1/ColorOS software family, so AX5 firmware must match the exact model string (CPH1851/CPH1851EX) to avoid baseband and partition incompatibilities. For most repairs, A.15 is the best starting point, and stepping down to A.12/A.11 is only recommended when a particular flashing tool version fails to complete on newer packages.

Complete Device & Firmware Overview

Device Name:: OPPO AX5 (CPH1851).
Model / Branch:: CPH1851 / CPH1851EX (EX builds shown by firmware collections for AX5).
Chipset:: Qualcomm Snapdragon 450 (SDM450) with Adreno 506 GPU.
OS Base (typical):: Android 8.1 with ColorOS 5.1 is widely listed for AX5 CPH1851.
Firmware Type:: Service-style stock firmware packages (large archives commonly used for repairs like bootloop/hang-on-logo and lock issues).
Build Naming:: CPH1851EX_11_A.xx where higher A.xx generally indicates a newer maintenance release.
Primary Flash Method:: MSM Download Tool is widely used as an after-sales flashing utility for OPPO/Realme devices (Qualcomm service flashing).
Required Tools:: Windows PC, OPPO USB drivers, MSM Download Tool, stable USB cable, and adequate disk space to extract 3–5 GB archives.
Common Repair Targets:: Hang-on-logo/bootloop and lock-related issues are frequently cited reasons for flashing AX5 firmware packages.

CRUCIAL WARNING: Flashing the wrong AX5 variant (non‑CPH1851/CPH1851EX), wrong build branch, or a corrupted archive can cause bootloops, loss of network/IMEI functions, or a hard brick—verify exact model and build before flashing, and avoid unnecessary downgrades.

Preparation Before Flashing

Click here for the OPPO AX5 (CPH1851) pre-flash checklist

Confirm the exact model string: Ensure the device is OPPO AX5 CPH1851 (or the EX branch CPH1851EX) before selecting firmware.
Back up personal data: Service flashing typically wipes user data; back up photos, chats, and authentication apps before starting.
Charge the battery: Keep 60%+ charge to prevent shutdown during flashing.
Install drivers and tool: Install OPPO USB drivers and MSM Download Tool on Windows, then confirm the PC detects the phone properly in the required mode.
Prefer newer builds first: Attempt A.15 (then A.12/A.11 if needed) rather than jumping straight to early builds like A.01/A.04.

How to flash Firmware Files to OPPO AX5 (CPH1851)

This simplified guide covers flashing builds like CPH1851EX_11_A.15_191230_5c53d686 using MSM Download Tool on a Windows PC, a commonly referenced method for OPPO AX5 service repairs.

Prep PC: Install OPPO USB drivers and MSM Download Tool, then extract the firmware archive (A.15 recommended) to a simple folder path.
Enter the required connection mode: Power off the phone and connect it as required by MSM Download Tool so the device is detected correctly.
Load firmware: In MSM Download Tool, select the extracted AX5 package that matches CPH1851EX and the intended A.xx build.
Start flashing: Begin the flash and do not disconnect USB until completion is reported by the tool.
First boot: Allow extra time for the first boot and system optimization, then verify network, stability, and boot behavior.

For a complete, detailed walkthrough of the MSM flashing workflow (drivers, detection, and recovery scenarios), follow the dedicated guide: MSM Download Tool flashing guide.

Frequently Asked Questions (FAQs)

Q1. Which AX5 firmware build is best for general repairs?: A.15 is the most practical starting point for CPH1851EX repairs, since later builds are commonly used to resolve hang-on-logo and stability issues compared to early releases.
Q2. What does “CPH1851EX” mean in these filenames?: Firmware collections for OPPO AX5 often publish EX-branch packages labeled CPH1851EX, and flashing should match the phone’s software branch to avoid incompatibilities.
Q3. Can these packages fix “stuck on OPPO logo” problems?: Yes—AX5 flash-file guides specifically reference using these stock ROM packages to fix hang-on-logo/bootloop behavior.
Q4. Is MSM Download Tool the correct flashing method for OPPO AX5?: MSM Download Tool is widely described as an after-sales firmware flashing utility for OPPO/Realme devices and is commonly shown being used for AX5 CPH1851 flashing.
Q5. Should A.01/A.04/A.05 be flashed on a phone currently running a newer build?: Early builds are typically downgrade targets only for specific service workflows; unnecessary downgrades increase risk and are not recommended when a newer stable build is available.
Q6. What Android version does OPPO AX5 typically run on these builds?: OPPO AX5 CPH1851 is widely listed as Android 8.1 with ColorOS 5.1.
Q7. What is the most common flashing mistake that causes failure?: The most common failure point is mismatching the model/branch (CPH1851 vs other OPPO models) or using an incompatible package, which is frequently highlighted in repair-focused flash-file pages.