The first developer beta of macOS 27 "Golden Gate," released June 8, 2026, immediately after Apple's WWDC keynote, has broken the ability to boot Asahi Linux on Apple Silicon Macs. Any dual-booting developer who upgrades to the beta will find their Linux partition invisible to the boot picker — with no data lost, but with no way to reach that partition until a workaround is applied or Apple fixes the underlying bug.
The Asahi Linux project issued an urgent public warning the following day, asking every user running Asahi alongside macOS to hold off on upgrading. "Do NOT upgrade to macOS 27 Golden Gate," the team wrote in a Mastodon post. The cause: Apple changed how the boot picker and Startup Disk applications detect valid OS boot volumes. When running from macOS 27, the Asahi partition simply does not appear.
There is no data loss. The Asahi partition still exists on disk and is intact. The problem is a detection failure, not a deletion. But a partition that cannot be seen cannot be booted, and that makes any affected machine functionally single-boot until a resolution is in place.
Apple Silicon Boot Picker Architecture Explains Why This Happens
Understanding why this broke requires knowing how Apple Silicon handles OS selection — because it is nothing like the UEFI or BIOS boot menus most developers expect on x86 hardware.
On Apple Silicon Macs, there is no firmware-level boot menu in the traditional sense. The entire boot picker — the screen that appears when you hold the power button and shows your available operating systems — is a full macOS application running inside the recoveryOS environment paired with the currently active default boot volume. Because it is a macOS app, its behavior is entirely determined by whichever version of macOS holds that default boot slot.
Apple's own boot chain goes from SecureROM to iBoot1, then to iBoot2, which validates and loads the OS. OS selection is managed entirely at the APFS container level through Boot Policies stored in the iBoot System Container (iSC). The boot picker scans APFS containers for volumes matching an expected layout; if that scan logic changes between macOS versions — as it did in macOS 27 — any volume not matching the new detection criteria simply does not appear in the list.
Asahi Linux registers itself as a fuOS (Fully Untrusted OS) entry. The project's custom bootloader, m1n1, is installed through the kmutil command, which inserts its hash into the container's Boot Policy. That registration remains intact after the macOS 27 upgrade — but the boot picker's container-recognition logic no longer surfaces the entry to the user. The partition is there. The Boot Policy is valid. The boot picker just does not offer it.
Not Just Asahi: Apple Silicon Dual Boot Broken More Broadly
The regression extends beyond Asahi Linux specifically. Early testing by AppleInsider confirmed that users running older versions of macOS on separate partitions — a straightforward macOS-to-macOS dual-boot setup — encounter the same boot-picker failures. The same detection logic that hides the Asahi Linux partition also fails to surface older macOS installations in some configurations, suggesting this is a broader multi-OS regression in Beta 1 rather than a change targeted at Linux.
Asahi Linux filed a bug report with Apple under reference number FB22994760 and believes the breakage is unintentional. No response from Apple had been received as of publication.
What to Do If You Are Already on macOS 27 Beta
Users who upgraded to the macOS 27 developer beta before seeing this warning have a path back. If your Mac also has a secondary installation of macOS 26 or an older version of macOS on a separate volume, setting that older installation as the default Startup Disk will restore access to the Asahi partition. The recoveryOS and boot picker will then run from the macOS 26 volume, where the detection logic still recognizes Asahi correctly.
For users who want to test the macOS 27 beta going forward, the recommended approach is to install it on a secondary volume — not as the primary boot OS — and keep macOS 26 as the default boot target. That configuration preserves Asahi access while still allowing Golden Gate experimentation.
The Asahi Linux installer has been patched to block new installations under macOS 27. Users attempting a fresh Asahi install on a machine already running macOS 27 as the default will be warned and blocked until either a workaround is developed or Apple resolves the detection bug.
macOS 27 Boot Picker Regression: Not the First Time
This is not the first time a major macOS version has broken Asahi Linux boot. When macOS Sonoma launched in 2023, an analogous regression caused widespread boot failures on newer MacBook Pro hardware. At the time, the Asahi team documented the problem and concluded that the only path to a full fix ran through Apple. "Apple broke this, only Apple can fix it," the team wrote in its Sonoma boot failure wiki entry.
That precedent points to a structural condition, not a one-off bug. Because the Apple Silicon boot picker is a versioned macOS application with no formally published or stable ABI for third-party OS detection, every major macOS release carries the theoretical risk of a similar regression. The Asahi team has no advance-warning mechanism — no developer documentation from Apple describing which aspects of the APFS container layout or Boot Policy structure will remain stable, and which may change. The consequence is that the project must reverse-engineer each major macOS release to confirm compatibility, a process that can take days to weeks.
macOS 27 is the first version of macOS to run exclusively on Apple Silicon hardware, dropping support for all remaining Intel Macs and making Apple's M-series chips the only supported architecture going forward. That milestone gives the regression added weight: the Apple Silicon platform is now the only game in town, and Asahi's role as the primary path for Linux on that hardware grows more significant as the Intel alternative disappears.
Will Future macOS Versions Keep Breaking Apple Silicon Linux Dual Boot?
The short answer is: possibly, and structurally yes. The Apple Silicon boot picker's behavior is defined by "whatever macOS does" — a deliberate architectural choice documented by the Asahi team from its earliest research into the platform. Apple made no promise of stability for the container-detection logic that the boot picker uses, because the platform was never designed with third-party OS developers as a first-class audience.
Apple's stated design goals for Apple Silicon boot include native dual/multiboot support, and the company explicitly built the ability to run third-party OS kernels via the fuOS mechanism without a jailbreak. But those goals apply to the underlying mechanism — the Boot Policy system, the fuOS hash registration, the SEP-authenticated security model — not to the higher-level macOS application that presents the UI for OS selection. That application is free to change its detection logic with each macOS version.
Until Apple either stabilizes the boot picker's volume-detection interface or provides third-party OS developers with documentation and advance notice of changes, the Asahi Linux project will need to verify compatibility with each new major macOS release before recommending upgrades. For now, the advice is clear: hold on macOS 27 if you dual-boot Linux.
Frequently Asked Questions
Is it safe to install macOS 27 beta if I dual-boot Asahi Linux?
No. The macOS 27 Golden Gate developer beta changes how the boot picker detects valid OS partitions, and Asahi Linux partitions are no longer visible when the boot picker runs from a macOS 27 volume. Your data is not at risk of deletion, but you will be unable to boot into Linux until you apply the workaround described above or Apple releases a fix.
How do I restore my Asahi Linux partition after upgrading to macOS 27?
If you have a secondary installation of macOS 26 or older on your Mac, set it as your default Startup Disk in System Settings. This causes the boot picker to run from the older macOS volume, where Asahi Linux partitions remain visible. If macOS 27 is your only macOS installation, there is currently no published workaround — monitor the Asahi Linux project's announcements for updates as Apple responds to bug report FB22994760.
Will future macOS versions also break Linux dual boot on Apple Silicon?
Possibly. Because the Apple Silicon boot picker is a macOS application rather than a firmware-level menu, its OS-detection behavior changes whenever macOS does. There is no stable published interface for third-party OS detection. The Asahi Linux project documented a similar regression when macOS Sonoma launched in 2023, and must verify compatibility with each new major macOS release. Apple has not committed to a stable detection interface for non-Apple operating systems.
Does this mean my Asahi Linux files are gone?
No. The partition and all data on it remain intact on your internal storage. The issue is entirely about partition visibility in the boot picker — the macOS 27 version of the boot picker does not detect the Asahi container correctly. No files have been deleted.
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