Using IPSW Builder

Once you have loaded an existing original Apple IPSW file that you obtained earlier (using the browse .ipsw button) you are ready to create a custom ipsw, click the "IPSW Builder" button. This will cause a window to appear with a few different selection items, these are listed as following:-

Enable baseband update - Determines if the baseband update should be enabled in the custom ipsw. Only check this button if you wish to update the baseband modem portion of your iPhone. Warming! This may remove previous baseband unlocks or other modifications that have been previously made. If in doubt leave it unchecked.

Neuter bootloader - This will enable "Bootneutering" to the baseband firmware allowing custom firmware to be installed onto the iPhone baseband by convincing the iPhone that it is secure. Arbitrary secpacks and fls files will be accepted when the device is in this state. In order to use these features you will need to locate the two bootloader files. Please note, these files are not shipped with Pwnage Tool.

Under the BootNeuter checkbox will present two new options that are selectable these are -

Updrade to 4.6       NB: Unless you understand this option you should avoid it.

Downgrade to 3.9  NB: Unless you understand this option you should avoid it.

Unlock baseband - This will enable the unlocking of the baseband to all networks using a custom "software unlock" process. This should be used if you plan to use a SIM card from a carrier other than the one provided by your original iPhone carrier.

Activate Phone - This will activate the phone so that it can be used with iTunes. This will bypass the Apple activation process and set the iPhone to be in an Activated state allowing access to the device's functions.

Use Custom Pictures - This option enables the use of custom iPhone graphics to replace the stock images that are used when the phone boots or goes into recovery mode.