HOWTO: Booting XP from an external USB hard drive

[gradenko]

[edit: you have to keep the 5GB NTFS parition on your internal drive for this to work]

Hello, I cannot find a working solution for this posted so I'll post the solution I came up with (well, cobbled together from other people's hard work). I am using a MacBook Pro and an external G-Tech Q drive that supports USB 2.0. While XP does not officially support booting from a USB drive there is a way around it.

This solution requires access to a PC and is a bit time-consuming.

1. Use BootCamp to create a 5GB XP partition.
2. Using a PC and your Windows XP SP2 CD, go through the following process to create a USB enabled XP SP2 installation CD: http://www.ngine.de/index.jsp?pageid=4176
3. Plug your USB 2.0 external drive into your mac.
4. Put your new XP SP2 CD into your MAC and boot holding down the "C" key.
5. XP installation should begin, when you get to the drive choice, be sure to choose your USB drive. You may have to pre-format this drive to NTFS, mine was already formatted.
6. You will get a screen warning you that drive C needs to be formatted. This is OK because XP needs to write some temporary data to the startup (internal) disk. It will format the 5GB XP partition you created in step 1.
7. Follow the installation prompts and when your Mac reboots be sure to hold down the Option key. You will get a choice to boot to either your OSX installation, XP or the XP CD. Choose the XP hard drive.
8. The normal XP installation will continue. You will get some warnings about unsigned divers. This is fine and is occurring because you tampered with the XP installation files in step 2. NOTE: My installation hung once here. I just reboot and tried from step 7 again and it worked fine.
9. Once XP comes up install your BootCamp device drivers.

Good luck! I just now finished this so I have some testing to do. A very big thank you to emmanual from ngine.

[sud0n1m]

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[gradenko]

Keep in mind there are some limitations to this so far and I'm hoping I (or someone else) can come up with a more complete solution (ie getting rid of the 5GB partition on the internal drive).

As it stands you end up with two drives in XP, a C drive and a D drive. The C drive is the 5GB partition and the D drive is your System/Boot partition. I'm not sure if you can even change the drive letter of the System/Boot partition without rendering the system useless...

[iFrodo]

Originally Posted by gradenko

[edit: you have to keep the 5GB NTFS parition on your internal drive for this to work]

Just a little question, once the installation is completely finished, is it possible to remove this partition (and boot directly on the external USB drive) with BootCamp assistant and so reclaim it for the MacOS X partition?

[blargity]

From the looks of things they're actually doing an entire XP install on the hard drive and then using the USB drive as simply a data disk. That's why the hard drive shows up as C: and the USB drive as D:. If they want to prove me wrong then a 100 meg partition on the hard drive should be more than sufficient to bootstrap.

[gradenko]

Ok, I'll prove you wrong . I am not using the external drive as a data drive, XP is booting from the USB drive. What's happening is the Windows installation is detecting an internal drive and wants to use the internal drive for the MBR. I just did an experiment where I re-partitioned my internal drive with 2 partitions a 6MB partition for NTFS and the rest for HFS, re-ran the XP setup, created the partition on my external USB drive first as NTFS, so it is now C, then formatted the 6MB partition on the internal drive so it is D and completed the XP installation on the external USB drive. While this is not perfect you only have to give up a very small portion of your internal drive for the MBR and everything else is run off the USB drive.

I am trying to figure out a way to completely remove the dependency on the internal drive. There seem to be two issues to work around:

1. XP does not allow for the swap file to be on an external drive.
2. If XP setup detects and internal drive it will force you to use it as the MBR, meaning the Boot.ini, NTLDR, and ntdetect.com will be put there.

From what I've read issue 2 may be worked-around using older USB drivers; so I am in the process of creating a new XP installation CD with the SP1 USB drivers to see if that works. Otherwise I'm out of ideas

So, this is not yet a complete solution. Technically you are still using the internal drive as your system partition (because the MBR is there) and the external drive as your boot partition (because windows is there).

[gradenko]

I tried using older USB drivers and the XP installation is still forcing me to put the MBR on the internal drive. For my final setup I created a 1GB NTFS partition on the internal MacBook drive to use for the MBR and the swap file. The rest of the internal drive is HFS for OSX. The windows system is then installed on the USB drive as are all of my Windows apps. Since I need to actually do some work on my system I'm going to leave it at that for now to get an idea of how stable working from Windows on a USB drive is.

I'll post more if I am able to get a swap file working on the USB drive. Also, a word of caution, this solution is obviously not supported by Microsoft or Apple so proceed at your own risk (backup your system, make sure you have spare time in case anything goes wrong, etc).

Good luck

[bgd]

Originally Posted by gradenko

1. XP does not allow for the swap file to be on an external drive.
2. If XP setup detects and internal drive it will force you to use it as the MBR, meaning the Boot.ini, NTLDR, and ntdetect.com will be put there.

From what I've read issue 2 may be worked-around using older USB drivers; so I am in the process of creating a new XP installation CD with the SP1 USB drivers to see if that works. Otherwise I'm out of ideas

Regarding point 1, if you have enough RAM (1GB+), then a possible solution would be to create a tiny RAMdisk in memory (~10mb) for the swapfile, for those utilities that need to write to a swapfile. For everything else, you would use the RAM as such. I know some have gotten this to work with the utility RAMDisk XP...

Regarding point 2, any NTFS formatted drive with Windows on it can be made bootable simply by putting boot.ini, ntldr and ntdetect.com in the root directory. Likewise, if you want to boot an external NTFS drive from an internal NTFS drive, then simply add a line for it in the internal drive's boot.ini and copy ntldr and ntdetect.com to the external drive...

As for the installer overwriting the internal drive's MBR, that can be easily avoided by temporarily disabling the internal drive in the BIOS/EFI interface before installing or simply by repairing the internal drive's MBR in the install CD recovery console (fixmbr). I'm not sure though how the fixmbr command would work with the OSX dual-boot feature (probably not to well), but there are also tools like MBRWiz that can easily backup and restore MBR tables, although with more than one drive one has to be careful which MBR is backed up/overwritten...

[JonM1827]

I was just looking around, and I saw this... maybe it could help

http://www.winusb.de/tutorial.htm

Hope this helps
-Jon

Sorry... I don't know why the link wasnt working... Hope this helps now

[tucdemonic]

my question here would be why external usb drive why not external firewire drive and has anyone tried this / gotten it to work...