Please choose the right version of Whited00r firmware to install on your device. Making the wrong decision wont break your device, but you might have to restore the device again because something could be dysfunctional (for example Push Notifications).
There are two different versions of the Whited00r firmware for iPhone 2G: Normal and Unlocker.
Many iPhone 2G’s have been exported worldwide, so lots of iPhone 2G users are looking for a carrier unlock to use their device with any SIM card. You should choose Whited00r Normal version only if you can legitimately activate you device via iTunes AND you don't need carrier unlock (so you are using the original SIM card, for example from AT&T). All other users should choose Whited00r Unlocker firmware. If you are not sure, use the unlocked firmware.
Whited00r Unlocker firmware needs a Push-Notifications patch after the installation. PushFixer.com
Required tools for installation are included inside the zipped archive you are going to download. Don't forget to unzip the compressed folder.