14. How to update the firmware for K11/K11 R2R?

Before upgrading the firmware for K11, please note the following:

1) Only Windows computers can be used to upgrade firmware, please use computers with Windows 10 or above;

2) In addition to connecting the K11 to the computer, it is recommended to unplug all other devices or decoders on the computer USB interface;

3) During the firmware upgrade process, please do not disconnect the power supply or unplug the USB cable. If there is a power outage, it will actively enter the firmware upgrade state the next time it is powered on.

Update steps: 

1. Install the Windows computer driver:

https://forum.fiio.com/note/showNoteContent.do?id=202105191527366657910&tid=17

2. Turn on K11, press and hold the knob for 2 seconds to enter the menu settings, and rotate the knob until the word "UPDATE" appears on the screen. Short press the knob again to enter the "Y/N" option, rotate the knob and select "Y", and short press to enter the firmware upgrade state. At this time, the word "RETURN" is displayed on the K11 screen. Connect the K11 to the computer via USB. 

3. Open the "GD32_MCU_HID_IAP_Programmer" burning tool (this tool requires no installation). Note: The setting of "IAP Device" must be "GD32 USB IAP in FS Mode", please do not change it!

4. Click "open" and select the file "k11_app-vxxx.hex".

5. Click "OK" to start the firmware upgrade. After the upgrade is completed, "Download successfully!" will be displayed. Click "确定" and then "Cancel" to exit the upgrade tool.

Note: As shown in the figure below, please click the "Cancel" button in this interface to exit the software; do not click "OK", otherwise the software will re-enter the upgrade state.

6. After the K11 firmware upgrade is completed, the word "RETURN" will be displayed on the screen. Short press the knob to see the "Y/N" option. Select "Y" to exit the upgrade mode. After that, the K11 will restart. You could go to the menu FWxxx to check the firmware version.