Can't cold boot Talos on a T2 Intel Mac

[dhess]

Bug Report

Using a USB boot drive, and having disabled the system's Apple-signed boot restrictions, I'm able to install Talos v1.3.7 on a T2 Intel Mac (iMac Pro (2017), in this specific case) just fine, and everything at runtime works as expected. kexec warm reboots also work fine. But as soon as I cold boot the machine, I get the firmware's "missing boot folder" start-up screen. Holding the Option key during boot doesn't show the EFI partition as a choice, either — the only option I get is to boot into Internet recovery mode.

rEFInd is a common solution to Linux booting issues on T2 Intel Macs, but even booting rEFInd from a USB drive or SD card doesn't give an option to boot Talos. rEFInd doesn't seem to recognize the EFI partition.

Booting into the Mac's recovery mode and running refind-install also doesn't work as expected. In this case, rEFInd's installer recognizes the EFI partition and tries to mount it (via mount -t msdos), but this fails with a cryptic Invalid argument message.

Is there something unusual about Talos's EFI partition?

One workaround is to boot from the USB drive that I used to install Talos, which seems to recognize the installed image and uses its config, but that isn't a good long-term solution since it would require updating the drive every time I also want to update the installed version of Talos.

Note that there was a similar issue reported in the Sidero Labs Community Slack last month, this time for a 2018 Mac mini: https://taloscommunity.slack.com/archives/CMARMBC4E/p1678790269057759

Description

Logs

Environment

• Talos version: v1.3.7
• Kubernetes version: v1.26.3
• Platform: iMac Pro (2017), using built-in (nvme) storage