Back in October I blogged about what's new in .NET Framework 3.5 SP1. I also talked about 3 problems that affect the CLR that can result when you install the service pack. Up until this point you'd have had to call Microsoft Customer Service and Support to obtain the fix package. There are plans to release a post SP1 rollup fix that will include these and fixes for some other issues.
However, to streamline things we've now been able to make these three fixes available on the MSDN Code Gallery hotfix site. This is a site where the developer products division make some (though not all) fix packages available for direct download:
KB957541 - Get the fix - "FIX: On a computer that has the .NET Framework 3.5 Service Pack 1 installed, an exception is thrown when an application calls the GetOptionalCustomModifiers method or the GetRequiredCustomModifiers method on a ParameterInfo object of a generic interface"
KB957542 - Get the fix - "FIX: On a computer that is running the .NET Framework 3.5 Service Pack 1, the JIT compiler and the Native Image Generator (Ngen.exe) that use the Mscorjit.dll file may generate incorrect code"
KB957543 - Get the fix - "FIX: An application that serializes and deserializes a generic class that has at least one static member fails on a computer that is running the .NET Framework 3.5 Service Pack 1"
Note: if you need fix KB957541 for Vista Service Pack 1 or Windows Server 2008, you will need to download the appropriate "Windows6.0" fix package for one of the other fixes (957542 or 957543). They both include the other fix.