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Working drivers for iMac 27" 2017 running Windows 10/11 — fixes Boot Camp WiFi slow speed, ethernet stuck at 100 Mbps, and driver installation failures on external USB SSD.
Boot Camp Assistant refuses to install drivers when Windows runs from an external USB drive. The standard workaround (BootCamp/Setup.exe) installs a broken WiFi driver. This package contains the correct, tested drivers with a one-click installer.
1. Double-click INSTALL.bat
2. Accept the UAC prompt (Yes)
3. Wait for completion (~2 minutes)
4. Restart
No internet connection required. All drivers are included offline.
| Component | Chip | Driver | Status |
|---|---|---|---|
| WiFi | Broadcom BCM43602 (14E4:43BA) | bcmwl63a.sys v7.35.118.83 | Fixed (866 Mbps) |
| Ethernet | Broadcom BCM57766 (14E4:1686) | b57nd60a.sys v214.0.0.1 | Fixed (1 Gbps) |
| Bluetooth | Broadcom BCM4356A2 (05AC:8296) | AppleBTBC.sys | Working |
| Audio | Cirrus Logic CS4208 | AppleAudio.sys + CS4208 | Working |
| GPU | AMD Radeon Pro 570/575/580 (Polaris) | AMD Adrenalin (auto-download) | Working |
| Chipset | Intel 100 Series / Sunrise Point | Intel SerialIO + ME | Working |
| Keyboard | Apple Magic Keyboard | Keymagic.sys | Working |
| Mouse | Apple Magic Mouse 2 / Trackpad | AppleWirelessMouse.sys | Working |
The WiFi driver in Apple Boot Camp Support Software (version 7.77.119.0) is broken on BCM43602. Symptoms:
- WiFi link speed drops to 27 Mbps on 5GHz 802.11ac
netsh wlan show driversshows0 MHz - 0 MHzfor supported channels- The same hardware delivers 500+ Mbps under macOS
Root cause: Driver 7.77.x fails to initialize the PHY layer correctly:
- Falls back to 20 MHz channel width (instead of 80 MHz)
- Uses 1x1 MIMO (BCM43602 is 3x3 capable)
- Cannot negotiate high MCS index rates
This package installs driver version 7.35.118.83 (from $WinPEDriver$ directory), which:
- Correctly negotiates 866.5 Mbps (80 MHz, 2 spatial streams, MCS9)
- Includes
bcmihvsrv64.dllfor proper WLAN management - Properly configures the radio for 5GHz 802.11ac
The installer automatically removes 7.77.x if present and disables Broadcom's MPC (Minimum Power Consumption) throttling.
The Broadcom BCM57766 supports Gigabit but may negotiate at 100 Mbps due to:
- Energy Efficient Ethernet (EEE) — causes negotiation failures on some switches
- Green Ethernet — reduces signal power below Gigabit threshold
- Bad cable — Gigabit requires Cat5e/Cat6 with all 8 wires
The installer disables EEE and Green Ethernet automatically. If still 100 Mbps after install: replace the Ethernet cable with Cat5e or better.
All iMac 2017 GPU variants use the same AMD driver package (Polaris architecture, device ID 1002:67DF). The installer automatically downloads the correct driver if internet is available.
| GPU Variant | Device ID | Notes |
|---|---|---|
| Radeon Pro 570 (4GB) | 1002:67DF | Base config |
| Radeon Pro 575 (4GB) | 1002:67DF | BTO upgrade |
| Radeon Pro 580 (8GB) | 1002:67DF | Top config |
Download links:
- AMD Auto-Detect & Install (Recommended) — detects your GPU automatically
- AMD Radeon Pro 500 Series Drivers — manual selection page
The installer will attempt to download the AMD Auto-Detect tool automatically. If offline, download manually after install.
Note: Apple's Boot Camp AMD driver is outdated and may cause display glitches. Always use the latest AMD Adrenalin driver directly from AMD.
Boot Camp Assistant checks for internal BIOS boot and fails silently on external drives. This affects:
- WinToUSB installations
- Windows To Go setups
- Any external USB SSD/HDD boot
This package bypasses that limitation — drivers are installed directly via pnputil without needing Boot Camp Assistant.
The installer swaps Command and Ctrl at the OS level:
| Physical Key | Windows Function | Use For |
|---|---|---|
| Command (Cmd) | Ctrl | Copy, Paste, Undo, Select All |
| Control (Ctrl) | Win | Start menu, Win+Tab, Snap |
This makes the keyboard feel like macOS — Cmd+C copies, Cmd+V pastes, etc.
The Apple Keymagic driver preserves native keyboard behavior:
| Key | Default (no Fn) | With Fn held |
|---|---|---|
| F1 / F2 | Brightness Down / Up | F1 / F2 |
| F3 | Mission Control | F3 |
| F7 / F8 / F9 | Prev / Play-Pause / Next | F7 / F8 / F9 |
| F10 / F11 / F12 | Mute / Volume Down / Up | F10 / F11 / F12 |
Brightness works out of the box — no additional software needed. Hold Fn to use the top row as standard function keys (F1–F12) in games or applications.
To revert:
Remove-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Keyboard Layout" -Name "Scancode Map"
# Restart requiredSince TRIM does not work over USB bridge chips, the installer applies these optimizations:
| Setting | Value | Reason |
|---|---|---|
| SysMain (SuperFetch) | Disabled | Excessive random reads on USB |
| Windows Search Indexing | Disabled | Continuous background I/O |
| Scheduled Defrag | Disabled | SSD wear with no benefit |
| USB Selective Suspend | Disabled | Prevents SSD disconnection |
| Disk timeout | Never | Prevents spindown logic |
| Power Plan | Ultimate Performance | CPU 100%, no core parking |
- Open Device Manager → Network Adapters → Broadcom 802.11ac
- Check driver version is 7.35.118.83 (not 7.77.x)
- If Windows Update reinstalled 7.77.x: run
INSTALL.batagain - Disable Windows automatic driver updates:
gpedit.msc → Computer Configuration → Administrative Templates → System → Device Installation → Do not include drivers with Windows Update
- MPC might have been re-enabled. Run in elevated PowerShell:
Set-NetAdapterAdvancedProperty -Name "WiFi" -RegistryKeyword "MPC" -RegistryValue 0
- Ensure Apple Bluetooth firmware loaded (check Device Manager for "Apple Broadcom Built-in Bluetooth")
- Remove and re-pair the device
- Set output device to "Speakers (Cirrus Logic CS4208)" in Sound settings
- If headphones not detected: reinstall audio drivers from
drivers/audio/
- Requires restart after install
- Verify:
HKLM:\SYSTEM\CurrentControlSet\Control\Keyboard Layout\Scancode Mapexists
imac-2017-windows-drivers/
├── INSTALL.bat # Double-click to install (auto-elevates)
├── install.ps1 # Main PowerShell installer script
├── README.md
├── LICENSE
└── drivers/
├── wifi/ # Broadcom BCM43602 — v7.35.118.83
├── ethernet/ # Broadcom BCM57766 — v214.0.0.1
├── bluetooth/ # Broadcom BCM4356A2 + firmware
├── audio/ # Cirrus Logic CS4208 + Apple Audio
├── gpu/ # AMD Radeon Pro 570/575/580 (auto-download)
├── keyboard/ # Apple Keymagic
├── mouse/ # Apple Magic Mouse + Trackpad
└── chipset/ # Intel 100 Series + Management Engine
Extracted from Apple Boot Camp Support Software 6.1 via Apple's software update catalog. The WiFi driver uses the $WinPEDriver$\BroadcomWirelessNIC version (7.35.118.83), NOT the BootCamp\Drivers version (7.77.x).
To refresh drivers: use Brigadier with model identifier iMac18,3.
- Mac model: iMac 27" 2017 (iMac18,3) — Radeon Pro 580, 16/32/64GB RAM
- Windows: 10 (21H2+) and 11 (any version)
- Boot method: WinToUSB, Rufus (Windows To Go), or internal Boot Camp
- Tested with: Windows 11 Pro 26200, Micron 512GB SATA SSD in USB 3.0 enclosure
MIT — use freely, no warranty.