Latitude 5590 - 3rd Party Boot Manager Support?

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@BoonieBoy wrote:
Yes, the Boot Loader Supports Secure Boot via UEFI. The issue is that the Boot Loader is that BCDEDIT commands are not successfully adding the Boot Manager. Works on Other Dell Laptops and most other Dell Models. I've seen issues before when certain Systems have BIOS/UEFI settings disabling the changing of Boot Manangers for security reasons. But I can't find any way to Select, Add, etc... Boot Managers. Often there is a UI to add a Boot Manager.... See An Example here for the Inspiron... https://i.stack.imgur.com/dj6qV.jpg Normally these values can be modified via BCDEdit or the UEFI. However, if the UEFI does not support modifying these or has security restricting their changes, the BCDedit commands are ignored... So while the Bootloader is properyl signed.....BCDEdit commands are failing to add any entries on the Latitude 5590.

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@BoonieBoy, BCDEdit doesn't touch the system's BIOS/UEFI settings.  It only affects the Windows BCD, which is an environment entirely contained in the Windows Boot Manager system bootloader.  So for example if you have a dual boot Windows setup on a UEFI system, the system firmware will still only have a single entry for Windows Boot Manager, which will point to a bootloader file.  At a system level, it always loads that one bootloader -- but that Windows Boot Manager bootloader environment then has two BCD entries that you can select from.  The boot menu presented at that point has nothing to do with system BIOS/UEFI boot settings.  This design allows you to choose which OS you want to boot without having to manually rearrange your system-level boot order or press F12 to invoke the one-time boot menu every time you want to boot the non-default OS.

The Windows Boot Manager boot option is added to the UEFI firmware by Windows Setup when the OS is installed.  The reason is that whereas BIOS/Legacy options always pointed to a device, like your internal hard drive, UEFI boot options for local storage point to a specific bootloader file on a specific partition of a specific device.  That type of path has to be registered into the UEFI firmware, and again Windows Setup does this in the background by running the BCDBoot command, which is completely separate from BCDEdit.  Are you maybe confusing those two?

If the system's UEFI firmware didn't allow modifying the boot managers, it wouldn't be possible to install a new hard drive or even wipe an existing disk and reinstall an OS, because either of those actions would require a new boot entry to be registered into the UEFI firmware.