Asahi Linux 7.1: macOS 27 beta breaks booting, M3 support advances

Apple’s macOS 27 developer beta broke Asahi Linux on affected Macs, making the Linux boot entry vanish from both the Startup Disk app and the power-button boot picker. No data was lost — the partitions remained intact — but Apple’s boot tooling now requires an APFS metadata flag marking a volume as bootable, something it had silently ignored since macOS 12. Setting that flag manually restores the boot option, so new Asahi installs now set it automatically, and the installer gained a repair mode (plus a Linux-side tool still under testing) for existing setups caught out by the upgrade. A second macOS 27 regression came from an SMC firmware update that changed a battery-management call from returning a 32-bit integer to a single byte, which could trick Asahi’s power driver into staging an emergency shutdown; kernel 7.0.12 now handles both firmware ABIs. The team stresses that developer betas should never run on production machines, since global firmware updates are effectively permanent and only reversible via a DFU restore.

On the hardware-enablement side, M3-series support is progressing quickly thanks to Apple’s habit of reusing IP across generations. Because the I2S audio controller, the numerically controlled oscillator clock source, and the speaker and headset amplifier chips are unchanged since M1, high-quality speaker and headphone output landed on M3 with little more than Devicetree tweaks and config files. The same conservatism made CPU frequency scaling, big.LITTLE core scheduling, and SMC hardware sensors nearly trivial to bring up, and PCIe, Wi-Fi, Bluetooth, NVMe, keyboard, and trackpad drivers are now functional on M3 machines, much of it driven by contributor Yureka.

The report closes on the harder frontier: firmware. Most peripherals speak through Apple’s RTKit framework, sometimes with an added EPIC abstraction (DCP, AOP) or third-party blobs (the Broadcom Wi-Fi/Bluetooth chip), but the Apple Video Decoder is an outlier that uses neither — an ARM Cortex-M3-based block that pushes the project toward writing its own firmware. Installer support for M3 isn’t ready yet, but the team signals rapid movement.