What is boot.ini?
In Windows 2000, Xp and Windows 2003 boot.ini file can be seen. Its default location is C:\(drive, where the default or Primary OS is installed). It contains boot configuration data. This file is used by these Operating Systems to display a menu of operating systems currently on the computer and allows users to select what operating system to load.
What about Windows 8, 7 or Vista?
Windows 8, Windows 7 or Vista works differently. If you try to boot these Operating Systems using BOOT.INI and NTLDR, it will fail. NTLDR can’t load Windows 8 even if you have the boot.ini entry. For example, if you install Windows 8 in unallocated space on a computer running Windows XP and look inside the XP partition, you will find that the boot.ini file is changed and two lines have been added before the original boot.ini script.
There is a hidden system partition. As the system partition does not have a drive letter assignment, it can’t be seen. BCD or Boot Configuration Data is stored in a folder named \boot on this system partition. Like Windows 7, Windows 8 uses a boot manager (bootmgr.dll) which consults with the BCD ( in Boot folder) to locate the boot loader ( winload.exe).
What is the location of bootmgr.dll in Windows 8?
Bootmgr.dll is a hidden system file and it is located generally in the root directory of C:\ drive (always not necessary, it depends on installation history). If you are confused, simply navigate to Disk Management. The drive labeled System, Active will be the location of bootmgr.dll file.
Change Boot configuration in Windows 8
You may change boot configuration by editing bootmgr.dll. But it’s not wise to mess with bootmgr.dll unless you have good knowledge about it. However if you are determined to change bootmgr.dll, it is advised to create a recovery image of your existing system.
There’s a utility tool, EasyBCD to edit Boot Configuration. It is free for limited and non-commercial use.