Base SDK 3.0 to SDK 4.0

Question

I installed SDK 4.0 and found that I lost access to all previous SDK versions prior to 3.2.

I have found a link to download SDK 3.1.3 so I have both .dmg install fil

Answer 1

Looks like a problem with apple. I am also getting: "Base SDK Missing" after installing Snow Leopard and the iPhone SDK 4. There is no Base SDK in my case. I'm a newbie to the system and meant to make this a comment, not an Answer.

UPDATE: After reading the readme that comes with the SDK 4 a little closer, I see that it (xCode 3.2.3 and it's iPhone SDK4) does not support iPhone prior to 3.2 - the solution is to install the older SDK in a different directory. Also, don't forget to update your device if you use the newer xCode/SDK.
ANOTHER UPDATE:
Please ignore this ANSWER and see the one above that was provided by aizuchi. Don't forget to read the part about Base SDK area being a different thing from Deployment.