you don't need to do recovery to get the update. the reason is probably because you are using a radio firmware version other than XXLA2, which is the one that came with IMM76I (4.0.4).
我的心得是root過的機子因為核心跟原廠的有差異,造成更新包檢查核心時發生錯誤,跟Recovery 完全沒關係. 只要先刷回原廠4.0.4(非root版),不要root,刷CWM,就可以透過install zip form sd的功能 Update到4.1.1,我就是這樣才刷成功的,遇到這種問題的大大不妨試試.