3 ((new)) — Mtk-su Failed Critical Init Step

This error message, "mtk-su failed critical init step 3", indicates that the mtk-su exploit script was unable to prepare your device's memory or kernel environment for the root privilege escalation.

Specifically, "Step 3" usually involves setting up the kernel memory mapping or creating the necessary kernel structures for the exploit to execute code. If this fails, it typically means the specific exploit binary you are using is not compatible with your device's hardware revision or firmware version.

Here is a troubleshooting guide to resolve this issue.

❌ When to give up on mtk-su

Stop trying if: Your security patch is 2020 or later, Android version 11+, or kernel version 4.14 or higher.
These are almost certainly patched. mtk-su failed critical init step 3

Final note

Step 3 failure almost always means the exploit is patched on your device. There is no workaround if the kernel vulnerability no longer exists. Proceed with unlocking the bootloader if you need root access.

Developer’s Note: Why Step 3 is So Sensitive

For the technically curious, “step 3” in mtk-su roughly corresponds to the do_root function after the selinux_set_root call. The exploit uses a technique called arbitrary kernel read/write to modify the current task’s credentials (cred structure). Step 3 fails when the kernel’s commit_creds() function returns an error or when the kernel’s task_struct validation detects an inconsistency—like a UID that doesn’t match expected security capabilities.

In short, modern kernels add integrity checks that older exploits simply cannot bypass. This error message, "mtk-su failed critical init step

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.

5. Alternative Root Methods (mTK-SU is deprecated)

It is important to note that mtk-su is largely considered a "legacy" method for rooting modern devices. If Step 3 fails, it is often because the exploit is too old for your current device state.

Recommended Alternatives:

• Magisk (The Standard): Most MTK devices can be rooted permanently by unlocking the bootloader and patching the boot.img file with Magisk.
  • Process: Unlock Bootloader (varies by manufacturer) -> Extract boot.img from stock ROM -> Patch with Magisk App -> Flash via Fastboot.
• MTK Bypass / MTK Auth Bypass Tools: If you are trying to root to unbrick the device or flash a ROM, use the SP Flash Tool with an MTK Auth Bypass utility (like the one by aic-mtk or libusb-filter). This allows you to flash custom recoveries or ROMs without needing mtk-su.

3. SELinux Enforcement State

While mtk-su attempts to set SELinux to permissive during step 3, some stock kernels have been compiled with CONFIG_SECURITY_SELINUX_DEVELOP disabled or have SELinux hooks that cannot be bypassed via the exploited primitive. If the exploit cannot disable or bypass SELinux, step 3 fails.

Deconstructing the Error: What is "Critical Init Step 3"?

To understand why step 3 fails, we must understand the steps that mtk-su takes internally. While the source code is not fully public (to prevent malicious repurposing), reverse engineering and community analysis have pieced together the general flow:

• Step 1: Check the device architecture and kernel version. Ensure the device is running a compatible MediaTek SoC (e.g., MT6735, MT6750, MT6765, Helio P-series, G-series).
• Step 2: Locate and access the vulnerable /proc or /sys entry points related to the MediaTek CCCI (Cross-Core Communication Interface) or similar kernel driver.
• Step 3: Execute the core memory corruption primitive. This typically involves sending a specific malformed IOCTL (Input/Output Control) command to the kernel driver. The goal is to overwrite a function pointer or disable SELinux (Security-Enhanced Linux) enforcement at the kernel level.
• Step 4: Spawn a root shell (/system/bin/sh) with the newly acquired privileges.

"Failed critical init step 3" means that the exploit’s attempt to trigger the memory corruption or privilege escalation primitive was rejected or did not produce the expected result. The kernel driver either ignored the malformed command, blocked it, or the memory address the exploit was trying to overwrite was no longer accessible. ❌ When to give up on mtk-su