Newer Dell systems, such as the Latitude XX90 series laptops, are unable to boot to internal boot devices when in Legacy boot mode. This article provides more information on this issue.
With the Boot option set to Legacy boot mode on newer series of Dell systems, you will be unable to boot to internal boot devices (including HDD, SSD, or eMMC storage devices). This issue may also occur after installing the operating system in Legacy Boot mode. A message to this affect appears in the system BIOS under the General/Boot Sequence settings (Figure 1):
Figure 1: Boot Sequence settings
If the message highlighted above is missing from the Boot Sequence page, or if the Legacy External Devices setting is missing from the Boot Sequence settings, then update the BIOS to the latest available version at Dell Support / Drivers & Downloads. Select BIOS under the drop-down Category menu and download and install the latest available BIOS update. The Dell system must be imaged in UEFI mode unless booting to an external boot device.
Article ID: SLN309720Last Date Modified: 09/15/2020 04:13 PM