Allow entries for both ntldr (windows XP) and bcd (windows 10) simultaneously.

[Godan]

This would be a fantastic feature for mbr setups. The W10 boot manager doesn't handle my voodoo5 video card properly and it would be fantastic if I could just load straight into xp from grub and then i can just set wbm to boot straight into w10 without a timer.

[Drummer]

Hi Godan,

This would be extremely difficult, if not impossible.
The issues are these:

The MBR code must be on disk 0 for BIOS firmware systems. There can only be a single MBR on that disk.

The MBR code is different for Windows 10 and XP systems. They cannot both exist on the same disk.

Both the XP and Windows 10 BIOS bootloaders expect the Windows directory to be on disk 0 partition 1. Not shareable.
This would cause many conflicts and compatibility problems as both Windows installations would have to be on the same partition.

I'm sorry, this is not feasible.

Thanks for understanding,

Dave

[Godan]

Ok, well thanks for the through explanation.

[Ed P]

I seem to recall a format option named GPT that allowed a USB drive to boot in Windows 10 and Windows XP systems. It supported 2 MBR's so maybe that would help Gordan.

No idea how to invoke/implement it at this point, the discussion wws over a decade ago.

[Ed P]

http://www.rodsbooks.com/gdisk/gdisk.html

[Drummer]

Hey Ed,

This old utility is to convert MBR disks to GPT.

So you wind up with a GPT style disk drive.

Thing is, Windows XP cannot boot from a GPT drive.
It can only boot from MBR style disks.

So this utility will not solve Godan's issue.

Thanks,

Dave

[Ed P]

GPT adds to MBR disks, it doesn't change them. A bootable MBR USB drive can have GPT added to it, without reformatting the drive, which allows the USB drive to be bootable on Windows 7 and Windows 10 systems. I've done it (years ago lol).

[Drummer]

Hey again Ed,

I looked over the GPT utility documentation and I don't see where this is possible.
At least on disk drives such as Godan is using as opposed to USB sticks.

Please show me the GPT utility command syntax you are referencing that adds additional MBR 's to a disk drive that is bootable by XP.

An example of the full command would be helpful.

Let me know.

Thanks,

Dave

[Ed P]

The original old utility I referenced has some limitations but this Windows app might be easier for you to try.

MBR2GPT.exe, located in the System32 folder, is a command-line tool that will help you convert a disk from Master Boot Record (MBR) to GUID Partition Table (GPT) partition style without modifying or deleting data on the disk.

mbr2gpt /convert

[Drummer]

Hey Ed,

Again, the MBR2GPT utility's sole purpose is to convert from MBR to GPT.
The resulting GPT disk is useless since XP will not boot from a GPT disk.
I have tried, it doesn't work.
XP simply says that no boot media is found.
Black screen.

Dave

[Ed P]

Interesting.

In reality, imo, MBR2GPT converts the LPT not the MBR so why XP doesn't boot is strange. Are you booting XP via Grub2Win or using the machine's F8/F12 key?

Windows 8 supports BIOS and EFI booting a GPT USB drive. Yrs ago my wife and I had different Windows 8 machines.

[Drummer]

Hey Ed,

I'm contacting you directly for further discussion of this.

Thanks,

Dave