Optional Patch - Get rid of "Crackling Noise" on aptX Low Latency Headphones

Disclaimer：Please contact Avantree Support BEFORE upgrading. Be aware that if you upgrade without prior consultation with Avantree technical support and the product dead due to DFU misoperation, the warranty is not covered.

Step 1: Device Firmware Upgrade (DFU) File

Please download the upgrade firmware file to your computer noting the save path. Please note you can not open this file directly, just to save and choose when you upgrade.

File: C81 FS priority

Step 2: Enter C81 into DFU Mode

Plug the Avantree C81 into the USB port of your PC ,didn't connect any devices, press MFB button for 10s until the LED is off.

Step 3: Download & Install CSR Bluesuite to Perform DFU

For Windows PC - Please follow the steps in Step-by-Step Bluetooth Device Firmware Update (DFU) Guide with Windows PC

For Mac Computer - Please follow the steps in Step-by-Step Device Firmware Update (DFU) Guide for macOS

Please feel free to contact support@avantree.com with any further questions about this product or the above DFU procedure.