You may occasionally see "Failed to mount /data" if the repack's decryption script doesn't match your specific firmware version. Screen Brightness:

Before diving into technical modifications, it's crucial to understand the hardware you're working with, as this dictates compatibility.

If you still want to try repacking, you’d need:

Go to Settings > About Phone > Tap "Build Number" 7 times > Developer Options > Enable USB Debugging. Step-by-Step: Installing TWRP Repack on Vivo Y71

You're looking for information on TWRP (Team Win Recovery Project) for the Vivo Y71, specifically on repacking.

. It runs a 1.4 GHz Quad-core processor with Adreno 308 graphics and ships with Android 8.1 (Oreo) layered with Vivo's proprietary Funtouch OS 4.0.

Replaces the basic button-only stock recovery with a full touch-driven UI. Decryption Support:

: The recovery must match the device's stock kernel architecture.

The device might not show an accurate battery percentage while in recovery mode. Fairphone Community Forum Installation Prerequisites To install this repack, you must use a PC with ADB and Fastboot installed: How to Hard Reset VIVO Y71 - Factory Reset / Wipe Data