No. Read below.
6.0.3-8754 is not update 12 and is definitely not a minor update. Re-imaging the USB key will have no effect whatsoever on the outcome.
DSM 6.0.3-8754 WILL NOT work with loader v1.01 as this is not some trivial minor update. Although the kernel is the same version (3.10.77) as 6.0.2, the kernel was recompiled by Synology and there has been enough changes in the code for the loader not to work as is. Looking at the logs I can see that some modules are failing to load which is a clear sign that the kernel includes some changes.
DO NOT UPDATE TO DSM 6.0.3-8754 or you will have a bricked box in a recoverable loop state from which you won't be able to come out. The only way as far I can tell is to either wipe the system partition and then reinstall 6.0.2 or access the system partition through a Live Ubuntu USB key and modify the version file to then be able to reinstall 6.0.2. You can try this with no warranties: http://xpenology.com/forum/viewtopic.ph ... lit=access
Also, search the forum extensively before attempting anything.
Can you explain how to wipe or modify version file with ubuntu live cd please?