I'm not sure specifically what you need answering, sorry about that, I will take a guess anyway :)
The 2 screws on the bottom of the i4 either side of the dock connector are usually pentalobe screws, you need a special tool for these as they are proprietary screws used by apple.
something like this will let you get them out and replace them with normal screws:
if this wasn't the answer/question you were hoping for let us know ;)
All the parts and tools needed to replace the 5-point pentaobe screws on the bottom of your iPhone 4 or 4S with Phillips screws. This way, you won't need special tools if you have an iPhone repair emergency. Compatible with all iPhone 4 and 4S models. Inc — 50+ available at 9.95 each.