The patch has been released. The zip file contains img file of a bootable USB drive. Please refer to
http://www.fit-pc.com/wiki/index.php/Fit-PC3_BIOS_Update for instruction how to extract an img file on a USB memory device.
To update the Realteck's Ethernet Controller efuse, please boot the Fit-PC3 from the prepared USB drive and run the rtupd.exe file. After the update process is finished, please disconnect the USB drive and reboot the system.
Update: There was a bug detected in this LAN controller update, and the file was removed. If you have downloaded it before: please don't apply it. The new release will be release ASAP. We apologize for any inconvenience.