A little background before I go into the details of this guide. If you install Vista Beta 2 on a MacBook using BootCamp Assistant, you cannot set the default startup disk at ease. You can only set Mac OS X as the default startup disk using the Startup Disk tool in System Preferences. You cannot set the Vista Beta 2 as the startup disk once you set the MacBook’s default startup disk as Mac OS X.
nvram is a command line utility to manage firmware NVRAM varialbles. Even though MacBook uses EFI instead of OpenFirmware, it still uses NVRAM to store boot information. After some experiments, I was able to use nvram to set startup disk to either Mac OS X partition or Vista Beta 2 partition. The following steps are for a dual boot machine whose startup disk is Vista Beta 2.
- Boot the machine to Mac OS X.
- Open up Terminal application and type in
to get root access.
- In the Terminal window, type in the following to save the Vista boot information to the windows.nvram file.
nvram -p > windows.nvram
- Open the Startup Disk tool in System Preferences and set the startup disk to Mac OS X.
- Reboot the machine to Mac OS X.
- Repeat step 2.
- In the Terminal window, type in the following to save the Mac OS X boot information to the mac.nvram file.
nvram -p > mac.nvram
Now you have two NVRAM files: windows.nvram and mac.nvram. If you want to set the default startup disk, just do the steps 1 ~ 2 and the following:
- Set startup disk to Vista Beta 2
nvram -f windows.nvram
- Set startup disk to Mac OS X
nvram -f mac.nvram
When you use the nvram command with -f switch, you might get an error message like this:
nvram: Error (-1) setting variable - 'efi-boot-device-data'
It’s OK. The system boots to the OS as we specified regardless the error.