How to Upgrade Forefront Unified Access Gateway (UAG) from RTM to SP2

If you have an RTM install of Microsoft Forefront UAG 2010 and want to upgrade to the latest Service Pack 2 it isn't the easiest or most direct process.  You have to jump through a few hoops, and in my case I had errors that prevented me from even running the install, including "Setup failed during Forefront UAG prerequisites installation", and a simple error 1603 saying check the logfiles which weren't helpful.  Eventually, this was my process, i hope this saves somebody else some pain and suffering.



The updates are not cumulative, so to get to UAG SP2 from RTM you must install UAG SP1, then UAG SP1 Update 1, then Threat Management Gateway Service Pack 2 and THEN UAG SP2.

1. Open UAG Manager, and edit any portal sites you have provisioned and make sure the download and upload policies are not set to Sharepoint or CRM specific policies.  I set mine to always for now, and made a note to go back and fix those later.
2. With Service Pack 1 downloaded I was not able to run it directly, I had to extract it using this command: 
1. UAGSP1_KB2285712_ENU.exe
3. Then from an admin command prompt launch the UAG-KB2285712-ENU.msp patch file.
1. Once the install is done restart your server.
4. Once it reboots log in, open an admin command prompt, and install the SP1 Update 1 UAG-KB2585140-v4.0.1773.10100-ENU.msp
5. Open UAG Manager and export the configuration, you will need it later.
6. Stop all of the Forefront services, and then install the TMG SP2 update from the admin command prompt
7. Then install UAG SP2: UAG-KB2710791-v4.0.2095.10000-ENU.msp from the admin command prompt
8. In my case the schema did not work, the server was effectively blank.  Therefore I had to use the UAGSchemaUpgradeUtil.exe file found in common\bin on the exported copy of the configuration to fix everything.  According to the technet article an in place upgrade shouldn't require this, but in my case it did.
9. Then re-assign your upload and download policies, and test everything to make sure your upgrade went smoothly.

HTH!

Credits:
How to fix error 1603
http://social.technet.microsoft.com/Forums/eu/forefrontedgeiag/thread/965f29fd-d7ec-44ab-b5ab-609eb24dc8fc