Great progress on Asahi. What's the firmware situation like in general ? Since firmware won't be redistributable, would users need to periodically 'fetch' it from Apple CDNs or OS images ? Also, in the past broadcom has been quite problematic for wifi. How is it on the new macs ?

There's two classes of firmware: the bits loaded pre OS boot by the OS loader (which runs before our Linux loader), and the bits loaded by Linux. Both classes come from macOS recovery images and our installer takes care of fetching that from Apple's CDN. For the pre-boot firmware, it just gets installed into the Preboot partition the same way it does for macOS, and we don't have to worry about it after that. For the firmware loaded by Linux (current list: WiFi, video decoder), I have a design for a vendor firmware mechanism where the installer copies a tarball to the EFI boot partition, and then distros will have a script that extracts that on first boot or when it changes.

Since Apple do not keep their firmware ABI stable across the board, we'll have specific firmware versions (=specific macOS versions they come from) "blessed" for Linux compatibility. For updates (bugfixes or security issues, chiefly) you'd re-run our installer which will eventually have an "upgrade my firmware please" mode. That would run from recovery mode, same as the original install. All this stuff is per-OS, so it does not affect any adjacent macOS install which will use its own firmware - you can upgrade macOS whenever you want without breaking Linux.

Wifi works fine (modulo some firmware support details that'll get ironed out); people have been doing performance and stability tests and there is no major issue. I've heard stories about bad radio performance on Macs in the past, but those are almost certainly due to using the wrong firmware or config. That's what my patch set fixes: we use all the same firmwares and configs that Apple does, so we get the same results.