Cause: You downloaded the wrong APK (Lite version) or your device is a counterfeit Yuyang King chip. Solution: Uninstall the app. Hard reset your Yuyang King device (hold multifunction button for 10 seconds). Download the "Full" APK from the QR code in your instruction manual.
Step 1: Enable "Unknown Sources"
Step 2: Source the Official APK
Step 3: Verify the Package Name
Step 4: Install and Grant Permissions
Cause: Battery level is too low (firmware requires >40% charge) or your phone locked during the update. Solution: Charge the Yuyang King device fully. Keep the app in the foreground. Disable "Battery Optimization" for the Yuyang King app in your phone settings.
Cause: Missing permissions or Android OS incompatibility (e.g., Android 14+). Solution: Go to App Info > Permissions and grant all permissions (Storage, Nearby devices, Location). If it persists, install an older version of the APK (e.g., version 2.1.4 instead of 2.2.0). yuyang king bluetooth app full
Warning: This is common. Always verify the MD5 checksum of the APK against the official source. A legitimate "full" update will never ask for SMS or contact permissions.