Developer Scott Reed recently uncovered a method of unlocking the Sony Xperia Z simply by entering a unique code in the emergency call screen.

The exploit, as demonstrated in a video Reed posted on YouTube, is simple -- just go to the emergency call screen, enter *#*#7378423#*#*, select Service tests, select NFC, select the NFC Diag Test, then press the home button when the test is completed. "This seems to be a very very easy way around the security and very easy to do," Reed wrote in a blog post.

On the xda-developers forum, Reed also noted, "One important thing I've noticed when showing this to people is once you've done it once [it] seems to screw up the locking ... the lock button then doesn't show the security screen and if you press home it will. Also once you've done it once you have to force close all of the test windows and actually unlock your phone by [pressing] home then unlocking."

In the notes below the YouTube video, Reed states that has been in contact with Sony security regarding the exploit, though it's not clear how long he waited after notifying Sony before he posted the video, which he says was created "to help push Sony towards releasing a fast security update."