M31 | Vbmeta Samsung

What is vbmeta?

vbmeta (Verified Boot Metadata) is a partition on Android devices that stores integrity information about the system, vendor, boot, and other critical partitions. It is the cornerstone of Android Verified Boot (AVB) .

When your Samsung M31 boots, the bootloader checks the vbmeta partition to verify: vbmeta samsung m31

That system images haven't been tampered with.
That only an official, signed version of Samsung software is running.

If vbmeta detects unauthorized changes (e.g., custom recovery or patched boot image), the device will either: What is vbmeta

Refuse to boot (displaying a red warning or "Verification failed").
Boot with warnings but with limited functionality (e.g., Samsung Knox permanently tripped).

Prerequisites

Samsung M31 (SM-M315F) with OEM Unlock enabled (Developer Options → OEM unlocking).
Windows PC with Samsung USB drivers installed.
Odin3 (patched version – e.g., Odin3 v3.14.1 or modded for Exynos).
SamFw Tool or Heimdall (optional, for advanced flashing).
Stock firmware for your exact M31 build (downloaded from SamFW or Frija).

4. The "VBMeta Disable" Process for M31

To gain root access (Magisk) or flash a custom recovery (TWRP), the user must flash a patched vbmeta image with verification and verity disabled. That system images haven't been tampered with

VBMeta on Samsung M31 — Informative Overview

1. Executive Summary

The vbmeta partition is critical to Android’s Verified Boot (AVB) process. On the Samsung Galaxy M31, this partition determines whether the device boots normally, enters a recovery state, or displays a "Custom Binary Blocked" warning. Modifying (flashing) or disabling vbmeta is the primary prerequisite for rooting, installing custom ROMs (like LineageOS), or flashing patched firmware images.

Method A: Using your PC (Recommended)

Extract Stock Firmware: Download the latest Android 13 (One UI 5.1) firmware for the M31. Open the AP_...tar.md5 file with 7-Zip. Inside you will find vbmeta.img.
Download Android Platform Tools: Get adb and fastboot on your PC.
Open Command Prompt: Navigate to the folder containing vbmeta.img and fastboot.exe.
Run the Patch Command:
```
fastboot flash vbmeta --disable-verity --disable-verification vbmeta.img
```
If fastboot doesn't work on the M31 (Samsung usually disables fastboot), proceed to Method B.