Sometimes the FixMeStick or StartMeStick for Mac will not successfully start after selecting EFI Boot in the Startup Menu.
Instead the computer will open Startup Disk Preferences and display an error message that "Security settings do not allow this Mac to use an external startup disk."
While this setting can be changed through accessing the Startup Security Utility, some computers will continue to block the use of FixMeStick or StartMeStick as a startup disk even after allowing external boot media or disabling other security features.
This is because Apple has recently implemented the use of the T2 Security Chip with the MacBook Air, MacBook Pro, and Mac Mini after previously only including it with the iMac Pro. The T2 Security Chip is a hardware-based component that integrates different system controllers for better performance and enables the use of advanced security features. These features are designed to ensure that only trusted operating systems can be installed on the computer, and is causing some issues with the ability to boot Linux-based operating systems on models containing the chip.
Unfortunately, FixMeStick and StartMeStick are incompatible with any Apple model using the T2 Security Chip, which includes the iMac Pro and 2018 editions of the MacBook Air, MacBook Pro, and Mac Mini. However, we are currently in the process of developing the ability to boot on these computers and will release an update to our software with added support in the future.
If you have any questions, please contact us.