Editing Multi-booting (section)

===Neutral MBR===
An alternative to storing GRUB in the MBR is keeping Windows' or other generic PC boot code in the MBR, and installing GRUB or another bootloader into a primary partition other than that of Windows, thus keeping the MBR neutral.<ref>{{Cite web |title=openSUSE Bugs/grub |url=https://old-en.opensuse.org/Bugs/grub#How_does_a_PC_boot_.2F_How_can_I_set_up_a_working_GRUB.3F |website=openSUSE Bugs/grub |access-date=22 January 2017 |date=28 January 2010 }}</ref> Operating system selection at boot time consequently depends on the bootloader configured within the primary partition that has the boot or "active" flag set on its partition table entry, which could be a bootloader of [[DOS]], [[OS/2]], [[eComStation]], [[ArcaOS]]<ref>{{Cite web |title=ArcaOS |url=https://www.arcanoae.com/blue-lion/ |website=Blue Lion, by Arca Noae |access-date=22 January 2017 |date=13 November 2016 }}</ref> or [[BSD]], in addition to Linux or Windows.

With the boot flag set on the Windows primary, the [[Windows Boot Manager]] can be used to [[chainload]] another installed bootloader through use of a program like [[EasyBCD]].<ref>{{Cite web |title=How to add an entry for a Linux distribution in Windows' boot menu |url=http://linuxbsdos.com/2012/07/21/how-to-add-an-entry-for-a-linux-distribution-in-windows-boot-menu/ |website=Linux BSD OS |access-date=10 July 2016 |date=21 July 2012 }}</ref> This means the active partition's boot manager will first prompt the user for selection what OS to boot, then load another if necessary, such as GRUB, even a bootloader installed to a logical partition, and then GRUB will load the Linux kernel as it normally would were GRUB installed to the MBR.

The active partition could also be one that exists for no purpose other than choosing an operating system to boot, such as the boot manager that shipped with IBM's OS/2 Warp and its derivatives.