KaiT2en Fedora

KaiT2en [ˈkaɪ̯zɛn] refers to the Japanese philosophy of "kaizen". Which means constant small improvements.

Kait2en is using DKMS modules to add T2 Mac driver support to stock Fedora.

It also ships with the latest workarounds to make suspend working and includes T2 specific apps and tools.

The DKMS modules in this repository build against the currently installed kernel. This makes it possible for developers to quickly test patches without the need of recompiling the kernel. Also users can profit quickly from the latest efforts. Modules and Kernels are updated separately. So you will always get the latest kernel from upstream Fedora and decide for yourself if you want to update the modules from this repo.

KaiT2en can also be installed on top of existing T2linux.org kernels. It blacklists already upstreamed drivers and replaces them with its own. Note there will be still remnants of T2linux stuff when doing so, what is not helpful when dealing with issues. That's why we recommend installing KaiT2en on top of stock Fedora.

KaiT2en will not work on other distros than Fedora. This was a deliberate choice. In the first place we want a unified clean platform for debugging. We do not support ports to other distros.

The repository is meant to be used as an offline USB kit. Copy it to a USB drive, keep that drive connected, and run all commands from the repository root unless a guide says otherwise.

The setup is intentionally explicit. You will use the terminal, inspect logs and know which file was installed where.

Start here

Read the howto documents in order:

1. Introduction
2. Get Broadcom firmware from macOS
3. Prepare macOS and the Fedora installer
4. Install Broadcom firmware on Fedora
5. Install KaiT2en modules and apps

macOS must stay installed. If you want to erase macOS completely, use the regular T2 Linux documentation instead.

Working state and remaining work

KaiT2en is meant to provide a usable daily-driver baseline on stock Fedora. Most hardware works because KaiT2en carries the missing pieces out of tree while the real fixes are prepared for upstream.

The table below is not just a feature checklist. It also shows where work is still needed before the KaiT2en patches can become normal upstream Linux support. Contributions that move these items toward clean upstreamable fixes are welcome.

Area	Daily-driver state	Upstreamed	Remaining work
Audio	Working	No	Provided through t2bce. Audio should be split out of BCE internals.
Bluetooth	Working	Partial	brcmfmac and hci_bcm4377 need firmware and suspend quirks.
Camera	Working	No	Provided through the T2 BCE path.
Hybrid graphics	Working	Partial	amdgpu and gmux behavior needs proper fixes instead of suspend-time workarounds.
Keyboard	Working	Yes	Depends on the T2 BCE VHCI path and KaiT2en input drivers.
Suspend	Working	No	We install suspend helpers for model-specific amdgpu and BCM4377 handling. Which need fixes in drivers.
Thunderbolt	Working	Yes	We added further fixes that need upstreaming
Touch Bar	Working	Yes	Depends on T2 BCE VHCI which is not upstreamed
Touch ID	Not working	No	Needs reverse engineering.
T2 AVE	Not working	No	Needs reverse engineering.
Trackpad	Working	Yes	Depends on T2 BCE VHCI which is not upstreamed
Wi-Fi	Working	Yes	Requires firmware copied from macOS. Firmware handling must stay user-local.

The largest remaining kernel task is t2bce aka apple-bce. It should be broken into smaller upstreamable pieces instead of staying as one large T2 bridge driver. Known areas are DMA which should support scatter-gather support, mailbox handling, VHCI, audio and suspend/resume ordering. Suspend in particular needs a fast reverse path.

Driver naming

KaiT2en renames drivers it maintains because the original Fedora, upstream Linux and older T2 Linux drivers must be blocked during boot. If KaiT2en used the same module names, the kernel arguments that block the original drivers would also block our replacements.

The new names also make logs, lsmod, DKMS state and bug reports easier to read.

KaiT2en driver	Replaces or carries	Upstream state	Function
hid_t2magicmouse	hid_magicmouse with T2 patches	Partial	Apple Magic Mouse, Magic Trackpad and T2 Wellspring trackpad HID support.
t2bce	apple-bce	No	T2 bridge controller, VHCI devices, audio and camera transport.
t2bdrm	appletbdrm	Partial	Touch Bar display DRM device for react-drm.
t2gmux	apple_gmux	Partial	GMUX handling on dual-GPU T2 Macs.
t2hid	hid_apple	Partial	Apple HID quirks for T2 keyboards and related internal input devices.
t2mfi_fastcharge	apple_mfi_fastcharge	No	iPhone and iPad fast charging on Apple USB controllers.
t2smc	applesmc, macsmc pieces	No	Fan control, battery charge limit, hwmon sensors and RTC through the T2 SMC.
t2thunderbolt	thunderbolt	Partial	Thunderbolt and USB4 controller support on T2 Macs.
t2touchbar_bl	hid_appletb_bl	Yes	Touch Bar backlight handling.
t2touchbar_kbd	hid_appletb_kbd	Yes	Touch Bar keyboard mode handling.

Contributing

Contributions are welcome, especially when they move KaiT2en fixes closer to clean upstream Linux support.

Please keep changes focused. A good contribution should explain what hardware was tested, which Fedora kernel was used and what changed in the logs or device behavior.

License

KaiT2en-owned scripts, howto documents, project text and helper code are MIT licensed.

Kernel modules, apps and third-party tools may include code with different origins. Those components keep their own licenses in their directories.