There’s a software update you might have missed: a new firmware for the Apple USB-C to MagSafe 3 Cable used to charge the newest MacBook Air and MacBook Pros.
It’s not clear what the firmware fixes or patches, but it’s unlikely to include any noticeable changes. According to Aaron Zollo on Twitter, the firmware version is 3.1.12 and has build number 10M1543. As far as we know, it’s the first time the firmware has been updated since the cable arrived in 2021 with the new MacBook Pro.
There’s no way to directly update the cable, but it should update automatically when plugged into your Mac. While you can check the firmware of your power adapter by attaching it to your Mac and clicking on the Apple logo in the top left corner of the menu bar, then About This Mac, System Report, and Power, it’s not clear how to check the specific firmware version of the cable. On Twitter, some users have reported that “the light on the cable went off then back on after about 10 seconds,” which could indicate that the firmware was installed.
In teardowns of the MagSafe cable, you can clearly see a circuit board with numerous chips similar to the MagSafe iPhone charger. In their teardown of the MagSafe Charger for the iPhone, ChargerLab unveiled an ST Arm Cortex M4 180Mhz CPU with a floating-point unit, and 512KB flash memory, so it’s likely a similar chip is in the MagSafe 3 charger.
Several MacBooks use the MagSafe 3 connector for charging, including the M2 MacBook Air, and the 2021 and 2023 MacBook Pros.
Update 2/17: Added information about the MagSafe iPhone Charger.