The first macOS Tahoe developer beta does not support the legacy FireWire 400 and FireWire 800 data-transfer standards, according to @NekoMichi on X, and a Reddit post. As a result, the first few iPod models and old external storage drives that rely on FireWire cannot be synced with or mounted on a Mac running the macOS Tahoe beta.
Unlike on macOS Sequoia and earlier versions, the first macOS Tahoe beta does not include a FireWire section in the System Settings app.
