The integrated circuit marked "AGD1 2022 FK9AH" is a 4 by 4 mm, micro-electromechanical (MEMS) gyroscope. It's situated on the iPhone 4's main circuit board.

See main story, iPhone 4 Teardown Telegraphs Future iPad Gyro.

Here's the same slice of the iPad's circuit board, showing an empty slot where the gyro was housed on the iPhone. Hence the assumption that the iPad is gyro-capable.

See main story, iPhone 4 Teardown Telegraphs Future iPad Gyro.