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macOS USB Support

Overview

The USB detection and management system now fully supports macOS using the native diskutil command-line tool.

What Was Changed

1. src/usb.py - Core USB Management

  • Added is_macos flag detection (Darwin system)
  • Implemented _detect_macos() method using diskutil list -plist external
  • Added _detect_macos_fallback() for systems without plistlib
  • Updated mount_device() to use diskutil mount on macOS
  • Updated unmount_device() to use diskutil unmount on macOS
  • Updated check_permissions() - macOS doesn't always require root for diskutil

2. flash_usb.py - USB Flashing Tool

  • Added macOS detection throughout the file
  • Updated check_root() to be more lenient on macOS
  • Implemented macOS USB detection in list_usb_devices() using diskutil list
  • Updated flash_image() to:
    • Use diskutil unmountDisk before flashing
    • Use /dev/rdisk instead of /dev/disk for faster writes
    • Use bs=4m instead of bs=4M (BSD vs GNU dd syntax)
    • Use diskutil eject after flashing

How It Works on macOS

USB Detection

# The system uses diskutil to detect external USB drives:
diskutil list -plist external

# Fallback method:
diskutil list

Mounting

# If not already mounted:
diskutil mount /dev/disk2s1

Unmounting

# Normal unmount:
diskutil unmount /Volumes/MyUSB

# Force unmount if needed:
diskutil unmount force /Volumes/MyUSB

Flashing (with root)

# Unmount disk before writing:
diskutil unmountDisk /dev/disk2

# Use raw disk device for faster writes:
dd if=image.img of=/dev/rdisk2 bs=4m

# Eject when done:
diskutil eject /dev/disk2

Usage on macOS

Basic USB Operations (No Root Required)

# Run the main application
python3 main.py

# The system will:
# 1. Detect USB drives using diskutil
# 2. List available devices
# 3. Mount/unmount as needed

Flashing USB Drives (Root Required for dd)

# Flash an image to USB
sudo python3 flash_usb.py

# The system will:
# 1. List external USB drives
# 2. Let you select one
# 3. Unmount all partitions
# 4. Write the image using dd
# 5. Eject the drive when complete

Benefits of Using diskutil

  1. Native macOS Tool - No additional packages required
  2. Proper Disk Management - Handles mounting/unmounting cleanly
  3. Fast Raw Disk Access - Using /dev/rdisk for better performance
  4. Safe Ejection - Ensures all buffers are flushed before removal
  5. Works Without Root - For detection and basic mounting operations

Differences from Linux

Operation Linux macOS
List USB lsblk diskutil list
Mount mount diskutil mount
Unmount umount diskutil unmount
Format mkfs.ext4 diskutil eraseDisk
Write Image dd bs=4M dd bs=4m (note lowercase)
Device Path /dev/sdb /dev/disk2
Fast Write /dev/sdb /dev/rdisk2 (raw device)

Testing

To test on macOS:

  1. Plug in a USB drive (⚠️ WARNING: Testing may erase data!)

  2. Test USB Detection:

    python3 main.py
# Should detect and list your USB drive

  3. Test Mounting:

    python3 -c "from src.usb import USBManager; usb = USBManager(); devices = usb.detect_usb_devices(); print(devices)"

  4. Test Flashing (use a spare USB!):

    sudo python3 flash_usb.py

Troubleshooting

"diskutil: command not found"

  • diskutil is a standard macOS command - you're not on macOS or have a very unusual system

Permission Denied

  • Some operations (like flashing) require sudo
  • USB detection and basic mounting usually work without root

Device Busy

  • Make sure the USB isn't being used by another application
  • Try force unmount: diskutil unmount force /Volumes/YourUSB

Slow dd Performance

  • Make sure you're using /dev/rdisk not /dev/disk
  • The code automatically converts disk to rdisk for better performance

Example Output

🔍 Detecting USB devices...
✓ Found 1 USB device(s)

Available USB Devices:
1. /dev/disk2 - 32.0 GB - SanDisk USB

✓ Selected device: /dev/disk2
✓ Using mounted volume: /Volumes/COLDSTAR
🔄 First instance boot detected on this machine...
✓ Boot instance marker updated
✓ First boot process completed - no restoration needed

Notes

  • macOS uses /Volumes/ for mount points instead of /mnt/ or /media/
  • Device names are like /dev/disk2 not /dev/sdb
  • Raw devices are /dev/rdisk2 for faster access
  • macOS typically auto-mounts USB drives, so explicit mounting is often unnecessary
  • The system handles all these differences automatically!