Reduce SQL Server 2012 install time on Server 2008R2 by pre-installing .Net4 / patches

If you are running SQL Server without clustering or other failover technologies you will want your SQL Server upgrade to run as quickly as possible so the users can get back the applications as quickly as possible. I always close all client connections, run an SQL back up of both client and system databases, stop SQL Services and set to manual, 'manually' copy the SQL data directories/log etc to a safe place before starting the upgrade. For me the downtime starts as soon as all the users have to come off so I can carry out a clean SQL backup.
Upgrading SQL2008R2 SP1 on Windows 2008R2 SP1 to SQL2012 a large amount of my downtime was SQL Server installing .Net4 and some subsequent .Net4 fixes before the ‘real’ SQL2012 upgrade started.
On subsequent installations I was able to reduce my downtime significantly by pre-installing .Net4 and the appropriate patches ahead of time.
Look in the redist\dotnetframeworks directory of your SQL Server installation media, it should look like the image below.

Run the dotNetFx40_Full_x86_x64 file first (or SC for server core install).
Once complete run NDP40-KB2468871-v2, and then NDP40-KB2544514, then switch to the appropriate x64 or x86 parent directory and run the file in there, eg NDP40-KB2533523. Now run SQL Server install and it should be much quicker. If you have many servers in this position it would be better to script it.
On Windows Server 2012 .Net4 should already be ‘pre-installed’ and this should not be necessary.
Happy upgrading!
Bizarre occurrence!
During one early upgrade I had copied the SQL installation media to the local server and then run the SQL installer from that server itself and SQL setup crashed installing .Net4. On investigation of the (many!) set up logs, the actual dotNetFx40 file was not copied correctly from the master installation media and was corrupted during the copy. Fortunately the crash had no serious consequences and I installed .Net 4 manually as per above after copying new files over, but there was some concern seeing the SQL install crash as a test install on the same server in the lab had installed perfectly! This highlighted the speed advantage of preinstalling .Net 4. When you get a crash in the middle of an install it can be a major problem as various components are at different levels, and fixing the mess can be very time consuming.