This scenario is NOT supported, but I did it anyway, and so far everything seems to be running just fine. This upgrade was done in test environment and I don’t recommend doing this in production, unless you’re a TAP customer.
Uninstalling Windows Automated Installation Kit
Before running setup, you need to uninstall the previous RC version of Windows AIK.
Click Start, and type Programs and Features, and press Enter.
Select Windows Automated Installation Kit, and click Uninstall.
Click Yes to restart the server.
Log in as Administrator.
Installing System Center Configuration Manager 2007 SP2 RC
Click Configuration Manager 2007 SP2, to start the installation.
Select I accept these license terms, and click Next.
Specify the Alternate path, and click Next. The folder must exist and should be empty.
Get some coffee.
Click Begin Iinstall.
Updating the Boot Images
Start the console and navigate to Operating System Deployment and Select Boot Images.
Right-Click the Boot image (x86), and click Properties.
Select the Images tab, and verify that the OS version is 6.1.7600.16385. (Otherwise click Reload).
Select the Windows PE tab, and select Enable command support (testing only), if required.
Repeat this step on the Boot Image (x64).
That’s is… You are now running a fully unsupported version of Configuration Manager 2007 SP2 RC… :o)