The posted article is all about "Legacy GRUB". GRUB2 has some similarities but I still preferred to use the Stage 1 sector as a "downstream" VBR rather than MB

The posted article is all about "Legacy GRUB". GRUB2 has some similarities but I still preferred to use the Stage 1 sector as a "downstream" VBR rather than MBR. I wanted to keep the original DOS or Windows MBR in place on sector 0, since it reliably jumps to the VBR ("boot sector") of whichever primary partition is marked Active at the time. Each of the partitions can then contain a different OS completely independently, accessible from any bootmenu you "install" to any of the possible primary partitions. Or even on the primary partitions you could just put the OS's alone without any boot files, like is done on the logical (non-primary) partitions, in that case the boot loader, boot files, and boot menu themselves could be on a separate drive like a floppy. Using GRUB Stage 1 as an MBR was mainly for overcoming difficulties when wrestling absolute boot control from a DOS-based PC since the standard DOS/Windows MBR jumped directly to the active partition's VBR and a DOS/Windows9x VBR would not boot Linux. Alternatively with an NT5 VBR/bootloader you can boot Linux since you have boot.ini and other than booting directly to an NT5 system, you can configure boot.ini to jump to a file on a FAT or NTFS filesystem and the file can be a copy of a DOS VBR (usually named bootsect.dos), which would then allow an NT system to boot back to DOS or W9x residing on a FAT filesystem somewhere accessible. Then when Grub Stage 1 (or more) is present on the FAT or NTFS filesystem in the form of a file itself (call it bootsect.lin) it could be put on the boot.ini bootmenu right next to the DOS & NT(ARC) boot options, and it boots Linux from the partition having the grub VBR which had been captured as bootsect.lin. Grub Stage 1 either proceeds to the very next sector or jumps directly to the defined location of its next stage and then proceeds until it displays (or not if there is not more than one OS) its routine bootmenu showing the OS's that it has been configured to boot from using the particular grub.cfg file being accessed at the time. Up until UEFI you have been able to boot Linux from an NT bootloader, even up to Windows 10 when it's installed on an MBR/BIOS HDD layout, so I preferred to use a Windows bootloader for everything. Now with the UEFI/GPT approach the NT6 bootloader will not boot Linux so something other than Windows (like GRUB2) needs to be the bootloader which can boot Linux as well as Windows.