Reverse Engineering the iPod Classic's Undocumented Mikey Chip
12 hours ago
- #reverse-engineering
- #iPod-Classic
- #Rockbox
- Rockbox, a volunteer-maintained firmware for iPod Classic, lacked support for Apple's earbud remote due to an undocumented chip called 'Mikey'.
- Reverse engineering efforts uncovered that the remote uses analog signals and an identification chirp, with no public documentation available.
- By sweeping the Mikey chip's registers, the author found the correct mode (0x2f) to enable button reporting and decoded events for play/pause and volume buttons.
- Hardware limitations were discovered, including a delayed button release report after inactivity, requiring software workarounds like click-only handling for the center button.
- A driver was submitted upstream to Rockbox's Gerrit (change 7677), and a prebuilt image was released for users, enabling full earbud remote functionality on iPod Classic 6G/7th gen.
- The project highlights the value of reviving abandoned hardware through community-driven reverse engineering and open-source software.