Mtk-su Failed Critical Init Step 3 Link Review

Troubleshooting the “mtk-su failed critical init step 3” Error: A Comprehensive Guide

For years, mtk-su has been a lifeline for Android users with devices powered by MediaTek (MTK) chipsets. This powerful command-line tool, developed by XDA Recognized Contributor diplomatic, allows for temporary root access and the exploitation of CVE-2020-0069, a vulnerability in MediaTek’s kernel. However, as Android versions have evolved and security patches have rolled out, users are increasingly encountering a frustrating roadblock: failed critical init step 3.

If you see this error message in your terminal or command prompt, your exploit attempt has failed. But understanding why this happens is the first step to potentially fixing it—or accepting the limitations of your device.

In this guide, we will break down what “critical init step 3” actually means, why it fails, and what you can do about it.

Step 3: Temporarily Disable SELinux (if possible)

While mtk-su attempts to work around SELinux, you can help it by setting SELinux to permissive—though this often requires root itself (a chicken-and-egg problem). If you have an unlocked bootloader, flash a permissive kernel. If not, try: mtk-su failed critical init step 3

adb shell setenforce 0

(Note: On stock ROMs, this usually fails without root.)

3. Look for Alternative Exploits

Some newer MediaTek devices are vulnerable to other exploits such as:

• CVE-2021-0438 (MediaTek cmdq driver)
• CVE-2022-21781 (MediaTek ATCMD)

Tools like exploit or mtkclient (which uses brom mode, not an exploit) may serve your needs, though they are more complex. Troubleshooting the “mtk-su failed critical init step 3”

Decoding “Failed Critical Init Step 3”

When the exploit fails specifically at step 3, it means the first two steps succeeded—the vulnerability was triggered, and memory corruption likely occurred. However, when mtk-su attempted to finalize the privilege escalation (i.e., give your shell root permissions), the kernel either refused the operation or the process became unstable.

In simpler terms: You picked the lock, turned the key, but the door jammed. Step 3 is the most delicate part of the exploit because it requires the kernel to be in a very specific state.

Step 2: Use the Correct Version of mtk-su

Do not use ancient versions like v18 or v22. Download the latest official build (usually v33 or r24) from the original XDA thread. Place it in /data/local/tmp and set permissions: (Note: On stock ROMs, this usually fails without root

adb push mtk-su /data/local/tmp/
adb shell chmod 755 /data/local/tmp/mtk-su

Why Does Step 3 Fail? Common Root Causes

The error is not a generic "something went wrong." It is a specific indicator that the exploit’s core vulnerability has been mitigated. Here are the primary reasons:

4. Architecture Mismatch

Although rare, using the wrong binary version (e.g., running the 32-bit ARM binary on a 64-bit only kernel, or vice versa) can cause step 3 to fail. The memory offsets and IOCTL numbers differ between 32-bit and 64-bit environments.

Alternative Solutions If Step 3 Keeps Failing

If you have exhausted troubleshooting and still see failed critical init step 3, accept that mtk-su is dead on your current firmware. However, you have alternatives.