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#1 2012-12-02 04:42:06

lithium
Member
Registered: 2007-09-18
Posts: 63

[SOLVED] Dual boot with NTLDR on MBR

This is my first setup with the new-style install media without a "graphical" install script. For the purposes of not disturbing my existing Windows partition, I would like to keep NTLDR on the MBR and have it call into either GRUB or SYSLINUX.

The way I previously did this was I installed GRUB-1.x onto the linux partition then used dd to copy the first 512 bytes of that partition into a file (arch.bin) and then copied that file into Windows and edited boot.ini to point to that file. Also, I previously had only one big partition and a swap but I would now like to keep a separate /boot partition, formatted as ext2.

So, how can I install either SYSLINUX or GRUB2 onto a formatted ext2 partition? GRUB2 doesn't seem to like being installed onto a partition and SYSLINUX seems to modify the MBR every time you run "extlinux --install" so I am not sure that is safe to run. There isn't actually much mention of installing SYSLINUX without having it on the MBR, so I am not sure if that is even possible (though Wikipedia says that it is not MBR-only).

Also, since I will now have a separate /boot, should the bootloader be installed on the /boot or the root partition?

Thanks!

Last edited by lithium (2012-12-05 03:44:21)

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#2 2012-12-02 05:39:24

WonderWoofy
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From: Los Gatos, CA
Registered: 2012-05-19
Posts: 8,412

Re: [SOLVED] Dual boot with NTLDR on MBR

Have you even thought about trying the wiki page?

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#3 2012-12-02 06:17:34

lithium
Member
Registered: 2007-09-18
Posts: 63

Re: [SOLVED] Dual boot with NTLDR on MBR

Spent quite a while there, thanks. Most of dual boot content on the wiki is focused on using GRUB to boot Windows and not on using NTLDR to boot Linux.

I asked some very specific questions in my post. I'm not sure why you think your post is helpful. It's possible I missed something in looking at the wiki but you didn't point it out.

Last edited by lithium (2012-12-02 06:19:43)

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#4 2012-12-02 16:50:03

shulamy
Member
From: israel
Registered: 2010-09-11
Posts: 323

Re: [SOLVED] Dual boot with NTLDR on MBR

i think you sould ask it in microsoft forum.

ezik

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#5 2012-12-02 17:01:12

madeye
Member
From: Denmark
Registered: 2006-07-19
Posts: 331
Website

Re: [SOLVED] Dual boot with NTLDR on MBR

I would think it should still be possible to use the windows bootloader to chainload you linux. I haven't tried it in ages though.
As to the question where you should place the bootloader. It should be on the boot partition.

If I remember correctly I used the following page to help me the last time:
http://amardeepsidhu.com/blog/2007/05/0 … oot-linux/


MadEye | Registered Linux user #167944 since 2000-02-28 | Homepage

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#6 2012-12-02 18:31:04

lithium
Member
Registered: 2007-09-18
Posts: 63

Re: [SOLVED] Dual boot with NTLDR on MBR

Nothing to ask in a MS forum, I already know how to do the NTLDR portion. I've been doing it this way since I've been dual booting (10+ years).

My question is: how do I make SYSLINUX (or GRUB2) install onto a formatted partition and NOT onto an MBR?

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#7 2012-12-02 18:34:55

anonymous_user
Member
Registered: 2009-08-28
Posts: 3,058

Re: [SOLVED] Dual boot with NTLDR on MBR

Do the instructions on the wiki not work?

https://wiki.archlinux.org/index.php/Gr … nless_Disk

Sure its not recommended, but I don't think you will find a "recommended" way to install GRUB2 to a partition. Also don't forget you can still use grub-legacy from the AUR:

https://aur.archlinux.org/packages/grub-legacy/

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#8 2012-12-02 18:39:55

lithium
Member
Registered: 2007-09-18
Posts: 63

Re: [SOLVED] Dual boot with NTLDR on MBR

They don't actually work. It won't boot, complaining about a missing kernel. I figured that since this wasn't recommended (--force), there was something wrong with this method.

I didn't realize GRUB-legacy was in AUR. Is this possible with SYSLINUX, so as not to use legacy code?

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#9 2012-12-02 18:54:09

lithium
Member
Registered: 2007-09-18
Posts: 63

Re: [SOLVED] Dual boot with NTLDR on MBR

Hmmm...now that I re-read the extlinux man page, I guess the default --install option doesn't actually overwrite the MBR but rather the VBR? Is that correct?

edit: Confirmed! It doesn't overwrite the MBR, just the VBR. Makes sense.

Last edited by lithium (2012-12-02 19:05:22)

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#10 2012-12-02 19:30:49

ANOKNUSA
Member
Registered: 2010-10-22
Posts: 2,141

Re: [SOLVED] Dual boot with NTLDR on MBR

You can't actually use NTLDR to boot Linux; you can only use it to chainload a Linux bootloader.  It's just the reverse of the process you find on the Arch wiki; the GRUB-to-NTLDR (or Syslinux-to-NTLDR) method is the recommended way of dual-booting because NTLDR is designed under the presumption that Windows will be the only operating system you ever use, but is just versatile to boot multiple versions of Windows.  You can check out EasyBCD if you're insistant on doing it.

EDIT: I believe the 100 Mb "System Reserved" partition exists to facilitate Windows booting after the MBR is overwritten; at least, I don't remember the last time I overwrote the MBR with another bootloader and had Windows not boot.

Last edited by ANOKNUSA (2012-12-02 19:33:12)

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#11 2012-12-02 19:53:17

lithium
Member
Registered: 2007-09-18
Posts: 63

Re: [SOLVED] Dual boot with NTLDR on MBR

Success! I got it working with SYSLINUX.

ANOKNUSA wrote:

You can't actually use NTLDR to boot Linux; you can only use it to chainload a Linux bootloader.  It's just the reverse of the process you find on the Arch wiki; the GRUB-to-NTLDR (or Syslinux-to-NTLDR) method is the recommended way of dual-booting because NTLDR is designed under the presumption that Windows will be the only operating system you ever use, but is just versatile to boot multiple versions of Windows.  You can check out EasyBCD if you're insistant on doing it.

You're correct that it can't boot Linux, only chainload. However, I think it's somewhat presumptuous to say that it was designed assuming you will only ever boot Windows. It supports chainloading just fine and has thus, indirectly, been booting Linux for a long time. Also, GRUB2/SYSLINUX cannot actually boot Windows, only chainload NTLDR.

No need for EasyBCD or any other software.

ANOKNUSA wrote:

EDIT: I believe the 100 Mb "System Reserved" partition exists to facilitate Windows booting after the MBR is overwritten; at least, I don't remember the last time I overwrote the MBR with another bootloader and had Windows not boot.

Huh? What "system reserved" partition are you talking about? I don't have anything like that.

Thanks to all that helped.

Last edited by lithium (2012-12-05 03:44:06)

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