1. Please download the latest Thunderbolt driver by below link and install it.Intel® Thunderbolt™ driver ver: 17.4.80.550: http://download.asrock.com/TSD/Desktop/Driver/thunderbolt%28tm%2917.4.80.550_19h1.zip 2. After the latest driver be installed, please restart and go to BIOS/Advance to set [Thunderbolt support] to [Enable] 4. Open the “FWUpdateTool.exe” . The link to this is in the PDF linked above 5. Select the FW Image [ASROCK_Z390_PG_ITX_ac_LP_HR_2C_A1_rev20_TI_170628_noUVP_CNL], we have include it in the attached file. 6. Click the [Start Thunderbolt™ firmware Update]. The utility will flash the firmware image. 7. After Firmware was updated successfully, please read the warning message and click the “OK” 8. Please shutdown the system and remove the power cord to enter the G3 state for 1 minute. 9. The Thunderbolt™ firmware will be updated in next boot.