Ok, I finally managed to install Windows 7 on a external drive on my rMBP. I used a Buffalo mini Thunderbolt drive for the installation. Process was pretty much:
1 - Plug in thunderbolt drive
2 - Used BC assistant to install windows 8 beta (I only selected a 20GB partition)
3 - When windows asks for a install location, just pick the thunderbolt drive, it installs fine.
4 - After installation, run windows 7 installation and do a custom install replacing windows 8 on the thunderbolt drive.
5 - Installed all the bootcamp drivers.
Everything was working great except for the 20GB Bootcamp partition the internal drive which is empty.
I returned to BC assistant to remove windows 7 hoping that it would only repartition the internal drive but it seems to have altered the MBR or something as well, I had to start the whole process over.
When I had it redone I decided to download EasUS partition manager and resize the 20GB partition to 48MB. There was only about 24MB of data on this drive and I figured there may be boot records or something like that there so I just wanted to try to reclaim most of the 20GB.
Big Mistake.
OSX, gone. Windows, blinking cursor.
I have spent the better part of the day trying to restore the computer from a backup but it has been real pain, even the Recovery drive is gone now. I think I lost have it back now.
Anyway, I just wanted to share that much since I have not found anyone that has been able to get a running copy of windows on a rMBP. Hopefully someone else out there knows a little about the boot records and such to finish this procedure.
1 - Plug in thunderbolt drive
2 - Used BC assistant to install windows 8 beta (I only selected a 20GB partition)
3 - When windows asks for a install location, just pick the thunderbolt drive, it installs fine.
4 - After installation, run windows 7 installation and do a custom install replacing windows 8 on the thunderbolt drive.
5 - Installed all the bootcamp drivers.
Everything was working great except for the 20GB Bootcamp partition the internal drive which is empty.
I returned to BC assistant to remove windows 7 hoping that it would only repartition the internal drive but it seems to have altered the MBR or something as well, I had to start the whole process over.
When I had it redone I decided to download EasUS partition manager and resize the 20GB partition to 48MB. There was only about 24MB of data on this drive and I figured there may be boot records or something like that there so I just wanted to try to reclaim most of the 20GB.
Big Mistake.
OSX, gone. Windows, blinking cursor.
I have spent the better part of the day trying to restore the computer from a backup but it has been real pain, even the Recovery drive is gone now. I think I lost have it back now.
Anyway, I just wanted to share that much since I have not found anyone that has been able to get a running copy of windows on a rMBP. Hopefully someone else out there knows a little about the boot records and such to finish this procedure.