As stated in an earlier post about an error within my ZCM server during the update from to 10.2, I can no longer log into the ZCC. After working on a few of the TIDS and suggestions from other updates when people have had issues I found a few interesting items which I hope someone witll either be able to tell me how to get my system responding again or if I need to start from the beginning.

10.2 update stopped (accourding to the logs) at 43%
I can do a zac ref on the server and recieve no errors.
when I try to do a zman sui for the service pack I get error 11 which I am assuming is part of the last SP failure.
when I try to log in an agent I get an error stating the username is either incorrect or the Certificate is bad.
I do get a ZCC login page but after login I recieve no error or further data.

So my question(s) is.
1. Can I role back manually without ZCC access to so I can try this 10.2 update again?

2. Is the agent error stating a bad certificate possibly the cause to the server giving a login prompt but no error or page after login?

3. If I have to reinstall the server is there a method to install the 10.2 product over the top of the old install and still keep the old data in place?