When intel hades NUC connected to a LG 5k display via thunderbolt 3 interface, there is no way to boot from USB sticks.
NUC hangup if any key pressed when boot up.
No Fn displayed even quick boot is disabled and Fn hints is enabled in BIOS.
Everything works when connecting the NUC to a TV via HDMI port
Thunderbolt firmware version 33
bios version HN0058
Thunderbolt™ 3 Legacy Driver for Windows® 10 for Intel® NU
Version: 126.96.36.1990 (Latest)Date: 2/22/2019
also tried DCH driver, no difference.
Thunderbolt™ 3 DCH Driver for Windows® 10 for Intel® NUC
Version: 1.41.645.0 (Latest) Date: 4/8/2019