You will need to flash the complete, official stock Samsung firmware via Odin using the BL, AP, CP, and CSC slots to restore the phone to a factory-fresh state before attempting the unlock process again. Conclusion
A standard Google-provided blank VBMeta image flags verification flags to 0 .
You can now proceed to flash Magisk or your favorite Custom ROM without triggering an AVB bootloop. Troubleshooting Common VBMeta Errors on the M31 Issue 1: Odin shows a "FAIL" error during flashing vbmeta samsung m31
If your phone says "Verification failed. Device cannot start restart your device to factory defaults," it means your system partition was modified but AVB was not successfully turned off.
Extract the AP_ file using a tool like 7-Zip. Inside, you will find vbmeta.img . Option 2: Using a Blank/Patched VBMeta You will need to flash the complete, official
Download the latest version of Odin for Windows.
Understanding the VBMeta Partition on Samsung Galaxy M31 The partition is a critical security component for any modern Android device, including the Samsung Galaxy M31 . It is part of the Android Verified Boot (AVB) system, which ensures that all software running on your device—from the bootloader to the operating system—is authentic and has not been tampered with. Troubleshooting Common VBMeta Errors on the M31 Issue
Tap . Magisk will modify the image to disable verification flags and save the output in your Download folder as magisk_patched_[random_strings].img . Step 3: Package for Odin Transfer the patched image back to your PC. Rename the file back to exactly vbmeta.img .