i86 update firmware problem

hi, i try to update my i86 ml(version: 1.75_rc1) to 1.75 version. i tried it using `check update from local storage` section but returned to me with `no update packet available`. of course i moved update.zip in to the root directory before and micro sd`s root also. i tried like this a couple times and didn`t work for me. Anyway, impulsively i clicked on the zip file and :smack: update started and reboot, crashed as like below
....
verifying update package...
Installing update...
Checking update package matching
assert failed: file_getprop(/tmp//android-info.txt, "board") == getprop("ro.product.board")
E: Error in /cache/update.zip
(status 7)
Installation aborted

Any opinion or advice?