This ability to display the pattern lock, is only when you have access to the gesture.key file that holds the pattern.
Access to this file is only possible when the device is not locked.
So, it will probably not help you with a locked device (unless the debug was left enabled).
RonS
I have been quite a bit of playing with Odin and rewriting the kernels - not found a suitable one yet.
Anyone have any suggestions?
I am actually writing a custom boot rom at the moment as part of a project, assuming the university allows me to hold the copyright then I will be releasing it to the forensic community free and open source. It is part of a bigger tool designed to allow physical acquisition of the NAND chip without booting the phone past the bootloader, with some other rather nifty features thrown on in 😉
In response to the OP, (from my LIMITED experiences) smudge attacks are worth a try but rarely work. Think about when you pull the phone out of your pocket, most of the time you stick your fingers on the screen in the process.
Lookup "ODIN+android" and go from there, just ensure what you do isn't going to overwrite the user partitions!
Cheers,
Tom