Latitude 7285 unable to boot to USB key with Fastboot set to Minimal

The Latitude 7285 2-in-1 may be unable to recognize a USB boot key from the pre-boot menu. Follow the steps in this article to resolve this issue and allow the USB boot key to be recognized.

Latitude 7285 2-in-1 USB boot key not recognized

When you need to boot to a USB key on the Latitude 7285 2-in-1 (for instance, when reinstalling the operating system from a USB boot key), the USB key may not be recognized from the pre-boot menu. This can occur when the Fastboot setting in the BIOS settings for the Latitude 7285 is set to Minimal. This Minimal setting will disable pre-boot functionality on the Thunderbolt USB-C port on the system.

To resolve this issue, you can temporarily disable Secure Boot in the BIOS settings for the Latitude 7285 following the procedure below.

Load BIOS default settings:

1. Reboot the Latitude 7285 and press the F2 key when the Dell logo appears to enter System Setup.
2. Click Restore Settings at the bottom of the main page (Figure 1):

   
   Figure 1: Click Restore Settings on the main System Settings page

3. Select BIOS Defaults from the pop-up menu that appears (Figure 2):

   
   Figure 2: Select BIOS Defaults from pop-up menu

4. Click OK to verify you wish to load the default settings (Figure 3):

   
   Figure 3: Click OK to confirm

5. Click the Exit button and the Latitude 7285 will restart.

NOTE: After loading the default BIOS settings, you may also need to verify that the following settings are enabled in the System Setup/BIOS under the System Configuration/Thunderbolt Adapter Configuration menu:

• Enable Thunderbolt Technology Support
• Enable Thunderbolt Adapter Boot Support
• Enable Thunderbolt Adapter Pre-boot Modules
• Security Level — No Security

Disable Secure Boot:

1. When the system reboots, press the F2 key when the Dell logo appears to enter System Setup
2. Go to Secure Boot > Secure Boot Enable and select Disabled from the menu. Click Yes on the pop-up message that appears to confirm (Figure 4):

   
   Figure 4: Disable Secure Boot in System Settings

3. Click Apply at the bottom of the page, then OK on the pop-up message that appears to confirm the changes.
4. Click Exit and the Latitude 7285 will reboot. The USB key should now be seen in the pre-boot menu.

Recover Secure Boot and Fastboot settings:

To recover the settings for Secure Boot and Fastboot back to their original configurations after using the USB key at boot, follow the steps below:

1. Reboot the Latitude 7285 and press the F2 key when the Dell logo appears to enter System Setup.
2. Go to Secure Boot > Secure Boot Enable and select Enabled from the menu. Click Yes on the pop-up message that appears to confirm the changes (Figure 5):

   
   Figure 5: Enable Secure Boot in System Settings

3. Go to POST Behavior > Fastboot and select Minimal from the menu. Click Apply at the bottom of the screen then Yes on the pop-up message that appears to confirm the settings change (Figure 6):

   
   Figure 6: Enable Minimal Fastboot in System Settings

4. Click Exit and the system will reboot. The BIOS settings will now be back to their original configuration.