Okay. I'm not sure if this is possible but tell me if it is.
Downgrade 1.1.1, install Oktoprep. Download the 1.1.2 firmware. Shift click update like you are downgrading it, except select the 1.1.2 firmware that you downloaded, the ipsw file. Then update it and let it install then run iJailbreak or whatever you use to jailbreak 1.1.2 and your there.
Would that work?
Downgrade 1.1.1, install Oktoprep. Download the 1.1.2 firmware. Shift click update like you are downgrading it, except select the 1.1.2 firmware that you downloaded, the ipsw file. Then update it and let it install then run iJailbreak or whatever you use to jailbreak 1.1.2 and your there.
Would that work?