SAN FRANCISCO, Oct. 17  Apple is opening up the iPhone  at least partly.

After engendering frustration from some customers and software makers, Apple has changed its policy to encourage independent developers to build programs for use on the iPhone.

Apple said that in February it would make available a developer’s kit, which would allow independent software makers to more easily create mobile games, navigation systems, screen-shot capture programs and other tools.

Several weeks ago, Apple released an over-the-air update to the iPhone that erased programs made by independent developers and caused some phones to freeze up.

The company is not changing a policy that forbids users from unlocking the iPhone to use it with carriers other than AT&T, Apple said.