Hello,
You could download the License Version of SEP 12.1 RU2 from: https://fileconnect.symantec.com/
For more Information on How to, check this Article:
Latest Symantec Endpoint Protection Releases - SEP 12.1 RU2 and SEP 11.0 RU7 MP3
This Symantec Endpoint Protection 12.1 product requires a Software License File to get it Activated.
However, In case you need a Trial Version of SEP 12.1 RU2, I would suggest you to download it from :
https://www4.symantec.com/Vrt/offer?a_id=117524
Use the same Symantec Community (SymAccount) user name and password to login.
Once you are logged in, you would be able to download the SEP 12.1 RU2.
Check this Screenshot -
Hope that helps!!