In the Audiovox SMT 5600, users cannot uncheck the “System” attribute on any files, regardless of whether they were there after a hard reset or otherwise. This makes them impossible to delete, which is a pain when one wishes to overhaul their start menu or, more important, get rid of obnoxious files that can’t be deleted. I have no idea where to get ROMs and can’t afford to unlock my phone, so I am unsure whether users of the c500 have the same problem.
However, there is a solution!
(1) On the SMT, the user cannot delete system files, although downloaded programs can delete them as far as I am aware. This leads to clutter, and seems to indicate that local commands can do so (assuming I am correct about downloaded programs).
(2) Using the elementary File Manager that came with the phone, the user can MOVE - and only move - system files. No other file explorer, including the amazing SmartExplorer, can even do this.
(3) I believe that anything put into the '\Temp' folder is automatically deleted after rebooting. At the very least, that folder is found empty afterwards.
WHICH MEANS THAT...
Combining (2) and (3), it looks as though any system file can be deleted. At least, I've never had any trouble with respect to any files located in '\Storage' and '\Storage Card'. Simply open file manager, then use Menu -> 1 File -> 4 Move To (or simply select six when in the main area of the browser), and move the naughty file into the “Temp” folder that is located between ‘Storage Card’ and ‘Windows’ at the top of the file tree. Restart, and – assuming your phone survives – enjoy your newfound freedom!
Two more points:
(4) I have no idea if this actually frees up memory or just makes things look pretty. Perhaps somebody can experiment with this and figure out whether the files are permanently erased and leave free memory behind. My instinct is that the OS uses that folder for precisely this purpose, disposing of temporary files that it would prefer you not meddle with. For example, if WMP updates the library, it must dispose of the old information - which was system locked - to make way for the new.
(5) USE WITH CAUTION. This trick should give you the power to delete important files. As I haven't gotten ahold of a Cingular ROM yet, I haven't studied anything to do with ROMs, including what files are considered part of them. However, if you can see ROM files with File Manager, then you can kill them. Which is probably a bad idea.
Hope this helps!