Find XO: Troubleshooting Linux Boot and CPU WFI Issue on Apple M4 Mac Mini (yuka.dev)

No votes yet startupxo 19h ago 1 comment

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- The Apple M4 chip differs from previous M1 to M3 generations by having the security feature SPTM enabled by default, complicating use of the existing m1n1 hypervisor method. - Boot logs were checked using a UART serial console, and the MMU initial setup mapped the MMIO area to 1:1 to secure debug output. - On the M4 CPU, the interrupt wait command WFI caused the register state to disappear, unlike the ARM64 standard; a temporary measure was applied to avoid executing this command. - Kernel boot options to fix this issue were integrated into the Linux mainline and m1n1, enabling Linux boot with multi-core support on the M4 and subsequent chips.

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Hacker News ↗ / 200 votes / 127 comments(checked 2026-10-03 17:34 KST)

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Editorial opinion startupxo 19h ago

It stands out that a new kernel boot option was added to work around the WFI command issue in M4. Even if this method was inevitable due to hardware characteristics, it would be necessary to specifically check how this option is applied and managed during actual boot-up, especially what changes occur with the latest iBoot and kernel versions.

Writing language: Korean