Wi-Fi Firmware

The Broadcom BCM4377b requires proprietary firmware files that cannot be bundled with the kernel or redistributed. They must be sourced from macOS or from the arch-mact2 community mirror.

Firmware Files Required

The MacBook Air 2020 uses board ID fiji. The following files must be present in /lib/firmware/brcm/:

File	Purpose
brcmfmac4377b3-pcie.apple,fiji.bin	Main Wi-Fi firmware
brcmfmac4377b3-pcie.apple,fiji.clm_blob	Channel/regulatory data
brcmfmac4377b3-pcie.apple,fiji.txcap_blob	Transmit calibration
brcmbt4377b3-apple,formosa.bin	Bluetooth firmware

Option 1 — Install via Package (Recommended)

The arch-mact2 mirror provides a apple-bcm-firmware package that contains firmware for all supported Apple Macs:

# The script handles this automatically
bash scripts/02-wifi-firmware.sh install-pkg

Or manually:

# Add the t2linux repo to /etc/pacman.conf first, then:
sudo pacman -Sy apple-bcm-firmware

Option 2 — Extract from macOS

If you have access to a macOS partition (or Time Machine backup):

# macOS firmware location
/usr/share/firmware/wifi/

# Copy the relevant files
sudo cp /Volumes/Macintosh\ HD/usr/share/firmware/wifi/C-4377__s-B3/*.bin \
    /lib/firmware/brcm/

# Reload firmware
sudo modprobe -r brcmfmac && sudo modprobe brcmfmac

Verifying Firmware is Loaded

# Check Wi-Fi device is recognised
ip link show | grep wlan

# Check for firmware errors in kernel log
sudo dmesg | grep -i brcmfmac | tail -20

# List Wi-Fi networks
nmcli device wifi list

Expected kernel log output (no errors):

brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac4377b3-pcie.apple,fiji
brcmfmac 0000:01:00.0: Direct firmware load for brcm/... succeeded

Backup and Restore

The 02-wifi-firmware.sh script supports backup and restore to preserve your firmware across reinstalls:

# Backup current firmware to ~/wifi-firmware-backup/
bash scripts/02-wifi-firmware.sh backup

# Restore from backup
bash scripts/02-wifi-firmware.sh restore