IMacs with the T2 Security Chip

I installed Ubuntu on a PC build. Its great. I wish to get linux on my iMac as well but I am having trouble.

Newer intel macs have a T2 security chip that prevents booting from an external drive. There are various internet articles that explain how you can get around this with recovery mode.

I have followed these instructions on my iMac with the T2 chip. I reboot (holding the option key) and I am given the choice of an EFI start up disk, which I select and hit enter. The screen darkens and the iMac acts as if it is booting but nothing ever happens. I eventually have to hold the iMac power button down to shut the computer off.

Here was my process:
I rebooted my iMac while holding cmd+R.
Recovery mode came up, I enter my password.
I select Utilities > Startup Security Utility on the menu bar.
I type in my password.
I activate the radio button next to ‘Allow booting from external or removable media’ and also ‘no security’.
I quit the Startup Security Utility.
I restart while holding option.
I am given the option of the EFI flash drive to boot from, so far so good.
I select it, hit enter, the screen darkens but Ubuntu never boots up.

2019 iMac 27”
OSX Monterey 12.2

Does anyone have more information on this?
Thanks for any help.


Hey @Fire!
I responded to your request in the previous topic you asked about it. :slight_smile:
See the attached link:

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Thank you! I’m going to look into this soon. Love this forum!

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