- Adding Boot Entries
- Adding a new boot entry
- Editing the boot menu
- Removing and deleting a boot entry
- BCD System Store Settings for UEFI
- Windows Boot Manager Settings for UEFI
- Device Setting
- Path Setting
- Other Settings
- Windows Boot Loader Settings
- Device and OSDevice Settings
- Path Setting
- Windows Memory Tester Settings
- Device Setting
- Path Setting
- Overview of Boot Options in Windows
- Boot Loading Architecture
- Boot Configuration Data
- Editing Boot Options
Adding Boot Entries
The first step in customizing boot options in operating systems is to add a new boot entry for an operating system. A boot entry is a set of options that define a load configuration for an operating system or bootable program.
You can have multiple boot entries for an operating system, each with a different set of boot parameters. Windows Installer creates a standard boot entry when you install an operating system, and you can create additional, customized boot entries for an operating system by editing the boot options.
You can add, delete, and change the options in the boot entry that Windows Installer created. However, it is prudent to keep the standard entry and, instead, add a separate entry that you customize.
To add a boot entry, copy an existing boot entry, and then modify the copy.
This topic applies to Windows Vista and later, Windows Server 2008 and later, and Windows Recovery Environment.
Adding a new boot entry
In Windows, you use BCDEdit to modify your boot options. To add a new boot entry, open a Command Prompt window with elevated privileges (select and hold (or right-click) Command Prompt and select Run as administrator from the shortcut menu).
NoteВ В Before setting BCDEdit options you might need to disable or suspend BitLocker and Secure Boot on the computer.
The easiest way to create a new boot entry is to copy an existing entry and then modify it as you need. To do this, use BCDEdit with the /copy option. For example, in the following command, BCDEdit copies the Microsoft Windows boot entry that was last used to boot Windows, identified as , and creates a new boot entry. The /d description option specifies DebugEntry as the name of the new boot entry.
If the command succeeds, BCDEdit displays a message similar to the following:
When you copy a boot loader entry that appears on the boot menu, the copy is automatically added as the last item on the boot menu.
The GUID in the preceding message (which appears between braces (<>)) is the identifier of the new boot entry. The /copy option creates a new GUID for the boot entry. You use the identifier to represent the entry in all subsequent BCDEdit commands.
If the command fails, be sure that you are running in a Command Prompt window with administrator privileges and that all of the command parameters are spelled correctly, including the braces around .
You can also add a boot entry using the /create option. This method is more difficult because you need to provide additional information about the boot entry type. You also need to specify the /application, /inherit, or /device options. For example, the following creates a new operating system boot entry called «My Windows Vista»:
When you use the /create option, the new boot loader entries are not added to the boot menu automatically. The /create option creates a new GUID for the boot entry. You must add the new boot entry to the boot menu by using the /displayorder option. You can place the boot loader entries in any order.
For information about the /create command parameters, type bcdedit /? /create in a Command Prompt window.
Editing the boot menu
In Windows, new boot loader entries are not added to the boot menu automatically. You can place the boot loader entries in any order.
You can use the /displayorder option to set the order in which the boot manager displays the boot entries on a multi-boot menu. The command has the following syntax:
The ID is the GUID of the boot entry or a reserved identifier, such as ). Separate each identifier with a space. Be sure to include the braces (<>).
For example, to add the DebugEntry boot entry to the boot menu after the entry, use the following command (remember to use ‘
You can also use the options /addlast, /addfirst, and /remove to order and remove items from the menu. For example, the following command adds the DebugEntry boot entry as the last item on the menu:
Removing and deleting a boot entry
The following command removes the <49916baf-0e08-11db-9af4-000bdbd316a0>boot entry item from the boot menu.
When you remove the specified boot entry using the /displayorder and /remove options, the boot entry is removed from the boot menu, but it is still in the BCD store. To completely remove a boot loader entry from the boot menu and from the store, use the /delete option.
To verify that the display order is correct, use the following command:
When you type bcdedit without additional parameters, BCDEdit displays the boot manager entry and the boot loader entries in the order that they will appear in the menu.
The Windows Boot Manager entry also includes the boot menu display order, as the following example shows.
BCD System Store Settings for UEFI
For a typical deployment scenario, you do not need to modify the BCD store. This topic discusses the various BCD settings in the BCD store that you can modify. On UEFI systems, this includes settings for the following boot applications:
The following sections describe the available settings for each of these boot applications in detail and how to modify each application for UEFI systems.
For simplicity, the BCDEdit examples in this section modify the BCD system store. To modify another store, such as a copy of the BCD-template, include the store name in the command line.
Windows Boot Manager Settings for UEFI
Windows Boot Manager (
The BCD settings for the device and path elements in Windows Boot Manager indicate the firmware boot manager. The template that is named BCD-template for Windows includes the following settings for Windows Boot Manager.
Device Setting
The device element specifies the volume that contains Windows Boot Manager. For UEFI systems, the device element for Windows Boot Manager is set to the system partition volume letter. To determine the correct volume letter, use the Diskpart tool to view the disk partitions. The following example assumes that the system has a single hard drive that has multiple partitions, including a system partition that has been assigned a drive letter of S.
The following Diskpart commands select disk 0 and then list the details of the volumes on that disk, including their drive letters. It shows volume 2 as the system partition.
If the system partition does not have an assigned drive letter, assign one by using the Diskpart assign command. The following example assumes that the system partition is volume 2 and assigns it S as the drive letter.
After you have determined the system partition volume, set the device element for Windows Boot Manager to the corresponding drive letter. The following example sets device to drive S.
Path Setting
The path element specifies the location of the Windows Boot Manager application on that volume. For UEFI systems, path indicates the firmware boot manager, whose path is \EFI\Microsoft\Boot\Bootmgfw.efi.
You can confirm that BCD-template has the correct path by enumerating the values in the store, as follows:
To explicitly set path to \EFI\Microsoft\Boot\Bootmgfw.efi, use the following command.
Other Settings
You should set Windows Boot Manager to be the first item in the display order of the UEFI firmware, as shown in the following example.
You should also specify the topmost Windows boot loader application in the Windows Boot Manager display order. The following example shows how to put a specified Windows boot loader at the top of the display order.
In the preceding example, is the identifier for the specified Windows boot loader object. The next section discusses this identifier in greater detail.
NoteВ В A multiboot system that has multiple installed operating systems has multiple instances of the Windows boot loader. Each instance of the Windows boot loader has its own identifier. You can set the default Windows boot loader (
Windows Boot Loader Settings
A BCD store has at least one instance, and optionally multiple instances, of the Windows boot loader. A separate BCD object represents each instance. Each instance loads one of the installed versions of Windows that has a configuration that the object’s elements have specified. Each Windows boot loader object has its own identifier, and the object’s device and path settings indicate the correct partition and boot application.
BCD-template for Windows has a single Windows boot loader object that has the following settings.
The identifier for this Windows boot loader is <9f25ee7a-e7b7-11db-94b5-f7e662935912>. You can use this GUID on your system or let the BCDEdit tool generate a new GUID for you.
To simplify BCDEdit commands, you can specify one of the Windows boot loaders in the BCD system store as the default loader. You can then use the standard identifier (
Device and OSDevice Settings
The following elements specify key locations:
The device element specifies the partition that contains the boot application.
The osdevice element specifies the partition that contains the system root.
For the Windows boot loader for EFI, both elements are usually set to the drive letter of the Windows system partition. However, if BitLocker is enabled or a computer has multiple installed versions of Windows, osdevice and device might be set to different partitions.BCD-template sets both elements to drive C, which is the typical value. You can also explicitly set the osdevice and device values, as shown in the following example. The example also assumes that you have specified the Windows boot loader for EFI as the default boot-loader object.
Path Setting
The path element of a Windows boot loader specifies the location of the boot loader on that volume. For UEFI systems, path indicates the Windows boot loader for EFI, whose path is \Windows\System32\Winload.efi.
You can confirm that BCD-template has the correct path value by enumerating the values in the store. You can also explicitly set the path value, as shown in the following example.
Windows Memory Tester Settings
The Windows memory tester (
NoteВ В Note: Intel Itanium computers do not include a Windows memory tester and do not require
BCD-template for Windows has the following settings.
Device Setting
For UEFI systems, the device element for the Windows memory tester is set to the system partition drive letter. The following example assumes that the system partition is drive S, as used in earlier examples.
Path Setting
The path element specifies the location of Windows Test Manager on the volume that the device element has specified. For UEFI systems, path indicates the EFI version of the application (\EFI\Microsoft\Boot\Memtest.efi).
You can confirm that BCD-template has the correct path value by enumerating the values in the store. You can also use the BCDEdit tool to explicitly set the path value, as shown in the following example.
Overview of Boot Options in Windows
The Windows boot loader architecture includes a firmware-independent boot configuration and storage system called Boot Configuration Data (BCD) and a boot option editing tool, BCDEdit (BCDEdit.exe). During development, you can use BCDEdit to configure boot options for debugging, testing, and troubleshooting your driver on computers running Windows 10, Windows 8, Windows Server 2012, Windows 7, and Windows Server 2008.
Administrative privileges are required to use BCDEdit to modify BCD. Changing some boot entry options using BCDEdit could render your computer inoperable. As an alternative, use the System Configuration utility (MSConfig.exe) to change boot settings.
Boot Loading Architecture
Windows includes boot loader components that are designed to load Windows quickly and securely. The previous Windows NT boot loader, ntldr, is replaced by three components:
Windows Boot Manager (Bootmgr.exe)
Windows operating system loader (Winload.exe)
Windows resume loader (Winresume.exe)
In this configuration, the Windows Boot Manager is generic and unaware of the specific requirements for each operating system while the system-specific boot loaders are optimized for the system that they load.
When a computer with multiple boot entries includes at least one entry for Windows, the Windows Boot Manager, which resides in the root directory, starts the system and interacts with the user. It displays the boot menu, loads the selected system-specific boot loader, and passes the boot parameters to the boot loader.
The boot loaders reside in the root directory of each Windows partition. Once selected, the boot loaders take over the boot process and load the operating system in accordance with the selected boot parameters.
Boot Configuration Data
Windows boot options are stored in the Boot Configuration Data (BCD) store on BIOS-based and EFI-based computers.
BCD provides a common, firmware-independent boot option interface for all computers running Windows 10, Windows 8, Windows Server 2012, Windows 7, and Windows Server 2008. It is more secure than previous boot option storage configurations, because it permits secure lockdown of the BCD store and lets Administrators assign rights for managing boot options. BCD is available at run time and during all phases of setup. You can even call BCD during power state transitions and use it to define the boot process for resuming after hibernation.
You can manage BCD remotely and manage BCD when the system boots from media other than the media on which the BCD store resides. This feature is extremely important for debugging and troubleshooting, especially when a BCD store must be restored while running Startup Repair from a DVD, from USB-based storage media, or even remotely.
The BCD store, with its familiar object-and-element architecture, uses GUIDs and names such as «Default» to precisely identify boot-related applications.
BCD includes its own set of boot options. For more information about these boot options, see BCD Boot Options Reference.
Editing Boot Options
To edit boot options in Windows, use BCDEdit (BCDEdit.exe), a tool included in Windows.
To use BCDEdit, you must be a member of the Administrators group on the computer.
You can also use the System Configuration utility (MSConfig.exe) to change boot settings.
To change boot options programmatically in Windows, use the Windows Management Instrument (WMI) interface to boot options. This BCD WMI interface is the best method to programmatically change the boot options. For information about the BCD WMI interface, see Boot Configuration Data WMI Provider in the Windows SDK documentation.
