Boot Windows 7 x64 on a MacBook Pro from a USB harddisk

So the last weekend I got a new game. The problem is that it doesn’t run on Mac OS X… 🙁

Wine doesn’t handle it and Parallels is something to forget.

Then I remembered I have an Intel processor inside my laptop! Well… that’s great! So let’s install Windows on Boot Camp! 😀

The only problem is that my internal harddrive is already with 4 partitions: EFI, HFS+, Linux Swap and Ext4!…

My first thought was to clean up the trash I have on my HFS+ partition and resize it. However, 30 GB is barely enough for Windows and the game. Then I thought of installing Windows on an external drive. The problem is that it doesn’t support that…

Here’s what I did:

My 1T external hdd is already with a GUID partition table, which means I can resize the only partition that’s in it (HFS+).

I fired up disk utility and resized it to 900GB, so that I got ± 100GB for Windows.

Upon connecting it to a Parallels VM running XP, I created a new partition and formatted it as NTFS.

Then I followed this tutorial. I borrowed my friend’s Tosh to put the Win7 X64 installation files on the newly created partition, as I needed an X64 machine to install a X64 system (it also works on 32-bit installations. In that case, you can use XP 32-bit).

In my case, I selected G: for both drive letters.

After completing the tutorial, the problem was that the Mac didn’t boot from the USB HDD, not even with rEFIt… :'(

According to rEFIt this happens due to a limitation on the Mac’s firmware.

So I had to put my head working: I had the Mac’s firmware, I had rEFIt and then… I had GRUB on /dev/sda4!!! 😀

However, I checked up some documentation and I thought it wasn’t that flexible as I wanted it to be. Then I found a great boot manager that’s called Plop. Plop is a boot manager that enables you to boot from most USB drives even when PC BIOSes don’t support it.

So the way to go was simple. I downloaded the latest version of Plop and booted Linux.
I copied plpbt.bin to /boot and added the following lines to GRUB’s menu.lst:

title Plop Boot Manager
root (hd0,4)
kernel /boot/plpbt.bin

–> The plpbt.bin file is on the ZIP file.
So now I have 3 boot managers:
The Mac’s firmware (to boot rEFIt), rEFIt (to boot GRUB) and Plop! I know it sounds crazy but it works flawlessly! I finished the Windows installation, installed the BootCamp drivers and now I have a perfectly working Windows install that runs from USB on my Mac! 😀

Of course it runs a bit slower compared to the internal HDD, specially when loading the NT kernel, but after playing with it for some time, you’ll barely notice it.

Hope this helps you the way it helped me! 😀

Good luck,


PS: If you want to spare your time, you may use a CD-ROM to boot Plop. Just take a look on Elmar Hanlhofer’s website. However, if you forget it at home,  it’s your fault! 😛

I’d like to thank Elmar Hanlhofer for developing such useful software. Please don’t forget us Mac users 🙂

yaroze / June 14, 2011 / Uncategorized

Leave a Reply

Your email address will not be published / Required fields are marked *