update.zip just for fixing file permissions, possible?

I soft bricked my colorfly g808 by following this guide (Japanese)

http://ift.tt/1AywF1a

I didnt do it using adb shell but using a terminal emulator in the phone itself, so I don't have ADB debug mode enabled.

the file in question is

/data/resource-cache/vendor@overlay@framework@framework-res.apk@idmap

I need to set its permissions to "644"

I have access to adb sideload by pressing the volume key while booting while connected by USB.

I tried several tutorials for making a custom updater-script but I always get the message "Installation aborted." when I try to install it. I tried signed and unsigned, by the way.

Is it possible at all to create an update.zip for just setting a permission on a file? do I need an "update-bonary"? (I tried including one from here http://ift.tt/1sfdmtq which I thought was targeted for my device)

My android version is 4.2.2... I think..