Follow the steps provided in this article to boot to an external device using USB TYPE-C connection for XPS, Precision and Latitude portable systems.
Cannot boot to external USB-C Connected device.
XPS, Precision and Latitude users may report they are unable to boot to externally connected USB Type-C devices.
The system may report a "Device not identified" error.
The default specification bypasses the USB boot sequence to reduce the boot times in the default configuration. Due to this default configuration the system does not boot to the external device.
Solution.
Please enable below two options to support boot from external device.
- At boot, Press the F2 key (or alternately press the F12 key then select the option to enter the BIOS setup).
- In POST Behavior, Select - Fastboot the select the Thorough option (Figure 1):

Figure 1: Select the Thorough setting for the Fastboot configuration in the BIOS
- In System Configuration -Select USB/Thunderbolt Configuration -Enable Thunderbolt Boot Support (Figure 2):

Figure 2: Enable Thunderbolt Boot Support under the USB/Thunderbolt Configuration settings in the BIOS
NOTE: You may also need to check to Enable USB Boot Support to recognize the USB boot device.
- In the General Tab, Advanced Boot Configuration, check Enable Legacy Option ROMs & Enable UEFI Network Stack if not already checked (Figure 3):

Figure 3: Enable UEFI Network Stack under the Advanced Boot Options settings in the BIOS
- Reboot the system, the USB Type-C device should now appear in the boot options.