Apple CEO Tim Cook said he was apologizing "deeply" for slowing older iPhones, saying it was necessary to prevent the devices form shutting down unexpectedly.
The company is preparing a software update to allow iPhone owners to better monitor the health of their device batteries following public uproar. It also offered replacement batteries at a discount.
"We deeply apologize for anybody that thinks we had some kind of other motivation," Cook told US broadcaster ABC on Wednesday (Thursday in Manila).
"All batteries age over time and they become unhealthy at a point in time. An unhealthy battery has a probability that it will create an unexpected restart," Cook said.
With the update, users will know when Apple is "reducing performance" of their iPhone "by some amount," he said.
"If you don't want it, you can turn it off. We don't recommend it," he said.
"Our actions were all in service of the user. I can't stress that enough. Maybe we should be clear at a point in time, but our actions were always the purest," he said.