| Issue | Probable Cause | Resolution | | :--- | :--- | :--- | | | File placed in a subfolder or file renamed. | Move file to Root Directory; ensure filename matches original download. | | Device stuck on Logo Screen | Interrupted update or corrupted file. | Force restart (Hold Power button for 15s). If unresponsive, contact support for recovery mode instructions. | | Settings Reset | Standard procedure for major version jumps. | Reconfigure EQ settings, Bluetooth pairings, and screen brightness manually. |

If you encounter any issues during the firmware update process, here are some troubleshooting tips:

Do not power off the device during the process. Once finished, the device will reboot.

: If your screen goes black after an update, it might just be the brightness resetting to zero. Try shining a flashlight at the screen to see the menu and manually increase the brightness in settings. Obscure Chinese DAPs | Page 526 - Head-Fi

| Problem | Solution | |--------|----------| | Computer doesn’t detect DFU mode | Install driver, replace with WinUSB for the FA4 DFU interface. | | Update fails at 50% | Use a USB 2.0 port directly (no hub). Disable antivirus temporarily. | | Device no longer powers on | This is rare. Hold Vol - while plugging in to force bootloader recovery. | | Lost UAC1/UAC2 switching | After update, toggle the mode: Press Vol + & Vol – together for 3 seconds. |

The firmware usually comes as a .bin or .zip file. Do not extract it unless specifically instructed by the readme. Phase 2: Preparation

If you are looking to update the or a specific TWS module, the process differs (usually done via a dedicated app on Android/iOS). For the standard FA4 IEM, "installation" refers to hardware setup.