The file lists MR1 version number.... that would be easy to change.... the hard part is the release keys..... even with the space I would have that it would not have found the file...
I had the same problem with it shutting down and trying to install the update. What I did was right when it booted up I did a factory reset as fast as a could and that fixed the automatic shut down. After the I renamed the OTA update file, so hopefully that solves the problem.
apparently changing the file name doesn't work... o well
Easiest method to get out of the shut down loop is to boot into recovery (volume down held when powered off) and clear the cache from recovery mode. Then reboot and it will say update failed. Then you can disable updates with Root Explorer.