After installing Thunderbolt Firmware Update 1.2:
- Thunderbolt ports may not work.
- Target Display Mode may no longer work.
- The update may keep reappearing as available for download.
This occurs when a self-powered Thunderbolt device (other than a directly-connected Thunderbolt display) is connected to a Thunderbolt port while installing the update.
To resolve this issue:
- Shutdown your computer.
- Disconnect all Thunderbolt devices.
- Wait 10 seconds.
- If you are using a Mac mini with a Thunderbolt display, reconnect the Thunderbolt display directly to your computer via the Thunderbolt port. Do not connect other Thunderbolt devices at this time.
- Restart your computer.
- If the Thunderbolt Firmware Update 1.2 is offered, download and install it and restart your computer when asked. If the Thunderbolt Update is not offered, the update has installed correctly.
- Reconnect all Thunderbolt devices.