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take a razor blade or an exacto knife and cut along the edge of the glass by the chrome bezel on the bottom of the phone. you are trying to cut away any dirt or grime that may be holding it in place. your not going to got deap! and then try the suction cup. but with the glass broken you may not get a seal. you may have to use the razor blade or exacto knife to get down in there and pry it out. the glass is already broke so your not going to do much damage. go down an 1/8 inch or so and pry it out. it may take some doings.

good luck!
 
By the bottom close to the home button. Be careful not to pull so hard you rip the ribbon cables off the board at the top of the phone.
 
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