What this means
If your Windows PC is booting in EFI mode, Microsoft has blocked the loading of legacy or non-Windows
operating systems from the BCD menu.
This means that you can no longer use EasyBCD to add Windows 9x, XP, or Server 2003 entries to the BCD bootloader menu. You also cannot add DOS, Linux, BSD, or Mac entries. You can add multiple Windows Vista, Windows 7, Windows 8, and Windows 10 entries; and you can also boot into BCD-based portable media, such as WinPE 2.0+ images.
EasyBCD is 100% UEFI-ready
In UEFI mode, much of EasyBCD’s functionality will be disabled for the safety of your PC. It abides by the restrictions Microsoft has placed on the bootloader that will block any attempts to load non-Microsoft-signed kernels (including chainloaders) from the top-level BCD menu, and it will create 100%-compliant UEFI entries other installed Windows operating systems on your PC.
These limitations are not short comings of EasyBCD nor can they be lightly bypassed, they have been put in place by Microsoft
Option 3: Use GRUB2 EFI as your main boot manager
EasyBCD controls the Windows boot menu, and has traditionally been used as the primary boot manager. With EasyBCD, it is possible to add entries for Linux and older versions of Windows to the top-level BCD menu seen when your machine first boots. Since the Windows boot manager running in UEFI mode does not support the loading of legacy and non-Microsoft operating systems, another option is possible.
When installing Linux or any other 3rd party OS that ships with its own bootloader, instead of choosing to install GRUB to the bootsector as is traditionally done when opting to use EasyBCD to control your boot menu, choose to install GRUB to the MBR (or disk, in this case) and make it the main bootloader for your PC. You can add the Windows boot menu to the GRUB2 EFI boot menu – in this case, you’ll see GRUB’s boot menu when your PC starts, and from there you can choose Windows. You can still use EasyBCD to control the Windows boot menu and set up multi-boots and re-configure Vista+ entries in the BCD boot menu, but with the GRUB2 EFI menu loading first, you can use that to boot into Linux and to chainload NTLDR to boot into Windows 9x.