Dead Rising 2: Off the Record Message Board  

It didn't trigger from in-game which is weird since it's LIVE and that usually handles patches via a (often somewhat forceful. ) auto update mechanic in-game from the interface.

Anyway someone managed to find the download link so here's that, maybe it'll help.

Link
(X-Box download website, cab file that can be unpacked more or less like a regular rar or zip archive and then a setup file and patch related cab file plus a MSI inside.)

(/f as a command parameter to setup.exe incase the patch doesn't find anything or stalls such as via a shortcut to setup.exe it would be as a generic example " C:\deadrising2otr\zpatch\setup.exe /f c:\deadrising2otr\ "

The patch works, but it also prevents your connecting to Live since it not officially released.

So that's why it didn't trigger in-game then, interesting.