diff --git a/docs/BUILDING.md b/docs/BUILDING.md
index 4672da2..4ef99cc 100644
--- a/docs/BUILDING.md
+++ b/docs/BUILDING.md
@@ -1,16 +1,33 @@
 # Building ISO Droid
 
-This document contains technical information for building and understanding ISO Droid.
+This document explains how to build ISO Droid from source and contribute to the project.
 
 ## Building from Source
 
 ### Prerequisites
 
-Before building the app, you need to obtain the `isodrive` binary:
+**1. isodrive Binary (Required)**
 
-1. The `isodrive` binary is compiled from [nitanmarcel/isodrive](https://github.com/nitanmarcel/isodrive)
-2. Place the compiled binary at `app/src/main/assets/bin/isodrive` before building
-3. The binary must be executable and compiled for the appropriate Android architecture (ARM64 recommended for modern devices)
+ISO Droid requires the `isodrive` binary to function. This binary is the actual tool that communicates with the Linux kernel's USB gadget subsystem to mount ISO/IMG files.
+
+- **Source**: The binary is compiled from [nitanmarcel/isodrive](https://github.com/nitanmarcel/isodrive)
+- **Why required**: Android apps cannot directly access USB gadget interfaces - they need a native binary with root privileges
+- **Location**: Place the compiled binary at `app/src/main/assets/bin/isodrive`
+- **Architecture**: Must be compiled for ARM64 (aarch64) for modern Android devices
+
+**How to obtain the binary:**
+
+Option 1: Download precompiled binary from [isodrive releases](https://github.com/nitanmarcel/isodrive/releases)
+
+Option 2: Compile from source:
+```bash
+# Clone isodrive repository
+git clone https://github.com/nitanmarcel/isodrive.git
+cd isodrive
+
+# Build for Android (requires Android NDK)
+# Follow the build instructions in the isodrive repository
+```
 
 ### Build Steps
 
@@ -22,311 +39,171 @@ cd ISODroid
 # Ensure isodrive binary is present
 ls -la app/src/main/assets/bin/isodrive
 
-# Build the debug APK
+# Build debug APK
 ./gradlew assembleDebug
 
-# Or build the release APK (requires signing configuration)
+# Or build release APK (requires signing configuration)
 ./gradlew assembleRelease
 ```
 
-The compiled APK will be located at:
+The compiled APK will be in:
 - Debug: `app/build/outputs/apk/debug/app-debug.apk`
 - Release: `app/build/outputs/apk/release/app-release.apk`
 
-## Technical Architecture
-
-### Overview
-
-ISO Droid is built using modern Android development practices:
-- **Language**: Kotlin
-- **UI Framework**: Jetpack Compose (Material 3)
-- **Architecture**: MVVM (Model-View-ViewModel)
-- **Minimum SDK**: 26 (Android 8.0)
-- **Target SDK**: 34 (Android 14)
-
-### Core Components
-
-#### 1. IsoDriveManager (`isodrive/IsoDriveManager.kt`)
-
-The central component that interfaces with the `isodrive` binary:
-
-- **Binary Extraction**: Copies the bundled `isodrive` binary from assets to app-specific storage
-- **Permission Management**: Ensures the binary has executable permissions (`chmod 755`)
-- **Command Execution**: Wraps all isodrive commands (mount, unmount, status checks)
-- **Device Support Detection**: Checks for configfs or sysfs USB gadget support
-
-```kotlin
-// Example: Mounting an ISO
-isoDriveManager.mount(
-    filePath = "/sdcard/isodrive/ubuntu.iso",
-    mountType = MountType.CDROM,
-    readOnly = true
-)
-```
-
-#### 2. RootManager (`root/RootManager.kt`)
-
-Handles all root access operations:
-
-- **Root Detection**: Checks for available root methods (Magisk, KernelSU, APatch, su binary)
-- **Cached Status**: Stores root grant status to avoid repeated prompts
-- **Command Execution**: Executes shell commands with root privileges
-- **Error Handling**: Captures stdout, stderr, and exit codes
-
-```kotlin
-val result = RootManager.executeCommand("isodrive status")
-if (result.isSuccess) {
-    // Parse output
-}
-```
-
-#### 3. USB Gadget Subsystem
-
-ISO Droid supports both modern and legacy USB gadget interfaces:
-
-**ConfigFS (Modern - Preferred)**
-- Path: `/config/usb_gadget/`
-- More flexible and feature-rich
-- Standard on Android 8.0+ devices
-
-**SysFS (Legacy)**
-- Path: `/sys/class/android_usb/`
-- Older interface
-- Fallback for older devices
-
-The `isodrive` binary automatically detects and uses the appropriate interface.
-
-#### 4. Mount Types
-
-**Mass Storage Mode**
-- Exposes the file as a USB mass storage device
-- Supports read-write mode for IMG files
-- Host PC sees it as a USB flash drive
-- Can be formatted with any filesystem (FAT32, NTFS, exFAT, ext4)
-
-**CD-ROM Mode**
-- Exposes the file as a virtual CD/DVD drive
-- Always read-only
-- Ideal for bootable ISOs
-- Host PC sees it as an optical drive
-
-### UI Architecture
-
-#### Jetpack Compose
-
-All UI is built using Jetpack Compose with Material 3:
-
-- **Declarative**: UI is a function of state
-- **Reactive**: Automatically updates when state changes
-- **Type-safe**: Compile-time checking for UI code
-
-#### Key Screens
-
-1. **MainScreen** (`ui/screens/MainScreen.kt`)
-   - File browser with OS icon detection
-   - Mount/unmount operations
-   - Status card showing current mount state
-
-2. **DownloadsScreen** (`ui/screens/DownloadsScreen.kt`)
-   - Curated list of OS download links
-   - Grouped by category (Linux, BSD, Windows, Recovery)
-
-3. **SettingsScreen** (`ui/screens/SettingsScreen.kt`)
-   - Root permission status
-   - Notification permission (Android 13+)
-   - Default ISO directory configuration
-   - App version and build information
-
-#### State Management
-
-Uses Kotlin StateFlow for reactive state:
-
-```kotlin
-data class MainUiState(
-    val isLoading: Boolean = true,
-    val hasRoot: Boolean? = null,
-    val isSupported: Boolean? = null,
-    val mountStatus: MountStatus = MountStatus.UNMOUNTED,
-    val isoFiles: List<IsoFile> = emptyList(),
-    // ...
-)
-```
-
-### OS Icon Detection
-
-Dynamic icon matching system:
-
-1. **Icon Storage**: SVG files in `app/src/main/assets/osicons/`
-2. **Dynamic Loading**: Icons are loaded at runtime via `AssetManager`
-3. **Fuzzy Matching**: Filename matching algorithm:
-   - Converts filename to lowercase
-   - Checks for icon name presence (e.g., "ubuntu" in "ubuntu-22.04-desktop.iso")
-   - Prioritizes longer matches (e.g., "linuxmint" over "linux")
-   - Prefers earlier position in filename
-
-4. **Rendering**: Uses Coil image library with SVG decoder
-5. **Badge System**: Small circular badge shows file type (ISO/IMG)
-
-### File Operations
-
-#### Creating IMG Files
-
-```kotlin
-// User specifies size (e.g., 4 GB)
-val sizeBytes = 4L * 1024 * 1024 * 1024
-
-// Creates sparse file using dd with progress reporting
-dd if=/dev/zero of=/sdcard/isodrive/custom.img bs=1M count=4096
-
-// Progress events are emitted via CreateImgEventBus
-```
-
-#### Rename/Delete Protection
-
-- Files currently mounted cannot be renamed or deleted
-- UI shows warning message and disables actions
-- Prevents accidental data corruption
-
-### Notifications
-
-Persistent notification while mounted:
-
-- **Information**: Shows mounted filename and mount type
-- **Quick Actions**: Unmount button in notification
-- **Foreground Service**: Ensures notification stays visible
-- **Auto-dismiss**: Notification removed after unmount
-
-### Data Persistence
-
-Uses Android DataStore (Preferences):
-
-```kotlin
-// Saves user preferences
-dataStore.edit { preferences ->
-    preferences[KEY_ISO_DIRECTORY] = "/sdcard/custom/path"
-}
-```
-
-Stores:
-- ISO directory path
-- Root grant status (from setup wizard)
-- App settings
-
-### Event Bus System
-
-Decoupled communication using Kotlin Flow:
-
-```kotlin
-// Mount events
-object MountEventBus {
-    private val _events = MutableSharedFlow<MountEvent>()
-    val events: SharedFlow<MountEvent> = _events.asSharedFlow()
-}
-
-// Emit event from notification
-MountEventBus.emit(MountEvent.Unmounted)
-
-// Observe in ViewModel
-MountEventBus.events.collect { event ->
-    when (event) {
-        is MountEvent.Unmounted -> updateUiState()
-    }
-}
-```
-
-## Dependencies
-
-### Core Libraries
-
-- **Jetpack Compose**: Modern declarative UI
-- **Material 3**: Design system and components
-- **Lifecycle & ViewModel**: Android Architecture Components
-- **DataStore**: Modern preference storage
-- **Coroutines**: Asynchronous programming
-
-### Image Loading
-
-- **Coil**: Image loading library
-- **Coil SVG**: SVG decoder for OS icons
-
-### JSON Parsing
-
-- **org.json**: Parsing OS download list (`assets/os.json`)
-
-## Testing
-
-### Manual Testing Checklist
-
-- [ ] Root access granted on first launch
-- [ ] USB gadget support detected correctly
-- [ ] ISO files mount successfully
-- [ ] IMG files can be created and mounted
-- [ ] OS icons display correctly
-- [ ] Unmount via notification works
-- [ ] File rename/delete protection when mounted
-- [ ] Settings persist across app restarts
-- [ ] Dark mode toggles correctly
-
-### Device Compatibility
-
-Tested on:
-- Modern devices with ConfigFS (Android 8.0+)
-- Legacy devices with SysFS (older Android versions)
-- Various root methods (Magisk, KernelSU, APatch)
-
-## Debugging
-
-### Enable Verbose Logging
-
-Check logcat for ISO Droid logs:
-
-```bash
-adb logcat | grep -i "isodroid\|isodrive"
-```
-
-### Common Issues
-
-**"Device not supported"**
-- Check for USB gadget support: `ls /config/usb_gadget/` or `ls /sys/class/android_usb/`
-- Verify kernel has USB gadget drivers
-
-**"Root access required"**
-- Ensure root manager (Magisk/KernelSU) is installed
-- Grant root access when prompted
-- Check `RootManager.hasRoot()` returns true
-
-**Mount fails**
-- Verify file exists and is readable
-- Check file isn't corrupted
-- Ensure no other USB modes are active
-- Try rebooting device
-
-### isodrive Binary Version
-
-Check the bundled binary version:
-
-```bash
-adb shell
-su
-/data/data/sh.sar.isodroid/files/isodrive --version
-```
-
 ## Contributing
 
-### Code Style
+### Adding OS Icons
+
+OS icons are displayed in the file browser when ISO/IMG filenames match the icon name.
+
+**Steps:**
+
+1. Add your SVG file to `app/src/main/assets/osicons/`
+   - Filename should be lowercase (e.g., `ubuntu.svg`, `archlinux.svg`)
+   - SVG should be simple and recognizable
+   - Recommended: Get icons from [Simple Icons](https://simpleicons.org/)
+
+2. The app automatically detects and matches icons:
+   - Filename `ubuntu-22.04-desktop-amd64.iso` → matches `ubuntu.svg`
+   - Filename `archlinux-2024.12.01-x86_64.iso` → matches `archlinux.svg`
+   - Matching is case-insensitive and searches for icon name within filename
+
+3. **Symlinks for aliases:**
+
+   Some distributions have multiple names. You can create symlinks:
+   ```bash
+   cd app/src/main/assets/osicons/
+
+   # Example: Manjaro uses Arch Linux icon
+   ln -s archlinux.svg manjaro.svg
+
+   # Example: Kubuntu uses Ubuntu icon
+   ln -s ubuntu.svg kubuntu.svg
+   ```
+
+4. Submit a pull request with your new icon(s)
+
+### Adding OS Download Links
+
+The Downloads screen shows curated links to operating system ISOs.
+
+**Steps:**
+
+1. Edit `app/src/main/assets/os.json`
+
+2. Add a new entry with all required fields:
+
+```json
+{
+  "name": "Ubuntu Desktop",
+  "category": "Linux",
+  "description": "Popular Linux distribution with GNOME desktop",
+  "icon": "ubuntu.svg",
+  "url": "https://ubuntu.com/download/desktop"
+}
+```
+
+**Field descriptions:**
+
+- `name` (required): Display name for the OS
+- `category` (required): One of: `Linux`, `BSD`, `Windows`, or `Recovery`
+- `description` (required): Brief description (one sentence)
+- `icon` (required): Filename of SVG in `osicons/` directory, or `null` if no icon
+- `url` (required): Direct link to download page or ISO file
+
+**Example with no icon:**
+```json
+{
+  "name": "Custom Linux",
+  "category": "Linux",
+  "description": "A custom Linux distribution",
+  "icon": null,
+  "url": "https://example.com/download"
+}
+```
+
+3. Test your changes:
+   - Build the app
+   - Navigate to Downloads screen
+   - Verify your entry appears in the correct category
+   - Verify the icon displays (if provided)
+   - Verify the link opens correctly
+
+4. Submit a pull request with:
+   - Updated `os.json`
+   - New SVG icon in `osicons/` (if applicable)
+   - Brief description of what you added
+
+### OS Icon Symlinks
+
+Some distributions share the same logo. Use symlinks instead of duplicating files:
+
+**Common symlinks:**
+
+```bash
+cd app/src/main/assets/osicons/
+
+# Arch-based distributions
+ln -s archlinux.svg manjaro.svg
+ln -s archlinux.svg endeavouros.svg
+
+# Ubuntu derivatives
+ln -s ubuntu.svg kubuntu.svg
+ln -s ubuntu.svg xubuntu.svg
+ln -s ubuntu.svg lubuntu.svg
+
+# Debian-based
+ln -s debian.svg kali.svg
+ln -s debian.svg raspbian.svg
+```
+
+**Why symlinks:**
+- Reduces APK size
+- Ensures consistency when upstream icon changes
+- Makes maintenance easier
+
+**Note:** Git tracks symlinks, so they work across all platforms when cloned.
+
+## Project Structure
+
+```
+ISODroid/
+├── app/src/main/
+│   ├── assets/
+│   │   ├── bin/
+│   │   │   └── isodrive          # Required binary
+│   │   ├── osicons/               # OS logo SVGs
+│   │   │   ├── ubuntu.svg
+│   │   │   ├── archlinux.svg
+│   │   │   └── ...
+│   │   └── os.json                # Download links
+│   ├── java/sh/sar/isodroid/      # Kotlin source code
+│   └── res/                        # Android resources
+├── docs/
+│   ├── BUILDING.md                 # This file
+│   └── screenshots/                # App screenshots
+└── README.md                       # Main documentation
+```
+
+## Code Style
 
 - Follow Kotlin coding conventions
 - Use meaningful variable names
-- Comment complex logic
 - Keep functions focused and small
+- Add comments for complex logic
 
-### Pull Requests
+## Testing
 
-1. Fork the repository
-2. Create a feature branch
-3. Make your changes
-4. Test thoroughly on a real device
-5. Submit a pull request with description
+Before submitting a PR, test on a real rooted Android device:
+
+- [ ] App builds successfully
+- [ ] New OS icon displays correctly
+- [ ] New download link opens properly
+- [ ] No crashes or errors in logcat
+
+## Questions?
+
+Open an issue on the repository if you need help or have questions about contributing.
 
 ## License