diff --git a/AVRsack.xcodeproj/project.pbxproj b/AVRsack.xcodeproj/project.pbxproj
index 7f16e7d..2a02e5a 100644
--- a/AVRsack.xcodeproj/project.pbxproj
+++ b/AVRsack.xcodeproj/project.pbxproj
@@ -19,6 +19,8 @@
 		951CD1771A2615000066C1A1 /* BuildProject in Resources */ = {isa = PBXBuildFile; fileRef = 951CD1761A2615000066C1A1 /* BuildProject */; };
 		95468DDF1A228BE600668EE2 /* ASHardware.swift in Sources */ = {isa = PBXBuildFile; fileRef = 95468DDE1A228BE600668EE2 /* ASHardware.swift */; };
 		95468DE31A228E1300668EE2 /* Defaults.plist in Resources */ = {isa = PBXBuildFile; fileRef = 95468DE21A228E1300668EE2 /* Defaults.plist */; };
+		95A7C6401A38914300EF1963 /* ASPreferences.xib in Resources */ = {isa = PBXBuildFile; fileRef = 95A7C63E1A38914300EF1963 /* ASPreferences.xib */; };
+		95A7C6461A3894C900EF1963 /* ASPreferences.swift in Sources */ = {isa = PBXBuildFile; fileRef = 95A7C6451A3894C900EF1963 /* ASPreferences.swift */; };
 		95BF80EB1A185C9E0004A693 /* ASFileTree.swift in Sources */ = {isa = PBXBuildFile; fileRef = 95BF80EA1A185C9E0004A693 /* ASFileTree.swift */; };
 		95EA32621A17B90600F66EB0 /* ACEView.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 95EA325B1A17B8DA00F66EB0 /* ACEView.framework */; };
 		95EA32651A17BA8C00F66EB0 /* Cocoa.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 95EA32631A17BA8C00F66EB0 /* Cocoa.framework */; };
@@ -80,6 +82,8 @@
 		95468DDE1A228BE600668EE2 /* ASHardware.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ASHardware.swift; sourceTree = "<group>"; };
 		95468DE21A228E1300668EE2 /* Defaults.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; path = Defaults.plist; sourceTree = "<group>"; };
 		958D76811A17DA1C00917D96 /* AVRsack-Bridging-Header.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "AVRsack-Bridging-Header.h"; sourceTree = "<group>"; };
+		95A7C63F1A38914300EF1963 /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.xib; name = Base; path = Base.lproj/ASPreferences.xib; sourceTree = "<group>"; };
+		95A7C6451A3894C900EF1963 /* ASPreferences.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ASPreferences.swift; sourceTree = "<group>"; };
 		95BF80EA1A185C9E0004A693 /* ASFileTree.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ASFileTree.swift; sourceTree = "<group>"; };
 		95EA32541A17B8DA00F66EB0 /* ACEView.xcodeproj */ = {isa = PBXFileReference; lastKnownFileType = "wrapper.pb-project"; name = ACEView.xcodeproj; path = ../ACEView/ACEView.xcodeproj; sourceTree = "<group>"; };
 		95EA32631A17BA8C00F66EB0 /* Cocoa.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Cocoa.framework; path = System/Library/Frameworks/Cocoa.framework; sourceTree = SDKROOT; };
@@ -171,6 +175,7 @@
 				95468DDE1A228BE600668EE2 /* ASHardware.swift */,
 				950AB9281A2D4F9B0033A9DA /* ASSerial.swift */,
 				951CD1731A23C9FC0066C1A1 /* ASBuilder.swift */,
+				95A7C6451A3894C900EF1963 /* ASPreferences.swift */,
 				951CD1761A2615000066C1A1 /* BuildProject */,
 			);
 			name = Source;
@@ -183,6 +188,7 @@
 				950AB9261A296A160033A9DA /* ProjIcon.icns */,
 				9501D80A1A17025C0034C530 /* MainMenu.xib */,
 				9501D8051A17025C0034C530 /* ASProjDoc.xib */,
+				95A7C63E1A38914300EF1963 /* ASPreferences.xib */,
 				95468DE21A228E1300668EE2 /* Defaults.plist */,
 			);
 			name = Resources;
@@ -318,6 +324,7 @@
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				95A7C6401A38914300EF1963 /* ASPreferences.xib in Resources */,
 				95468DE31A228E1300668EE2 /* Defaults.plist in Resources */,
 				9501D8071A17025C0034C530 /* ASProjDoc.xib in Resources */,
 				950AB9271A296A160033A9DA /* ProjIcon.icns in Resources */,
@@ -347,6 +354,7 @@
 				950AB9291A2D4F9B0033A9DA /* ASSerial.swift in Sources */,
 				9501D8021A17025C0034C530 /* ASApplication.swift in Sources */,
 				95BF80EB1A185C9E0004A693 /* ASFileTree.swift in Sources */,
+				95A7C6461A3894C900EF1963 /* ASPreferences.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -390,6 +398,14 @@
 			name = MainMenu.xib;
 			sourceTree = "<group>";
 		};
+		95A7C63E1A38914300EF1963 /* ASPreferences.xib */ = {
+			isa = PBXVariantGroup;
+			children = (
+				95A7C63F1A38914300EF1963 /* Base */,
+			);
+			name = ASPreferences.xib;
+			sourceTree = "<group>";
+		};
 /* End PBXVariantGroup section */
 
 /* Begin XCBuildConfiguration section */
diff --git a/AVRsack/ASApplication.swift b/AVRsack/ASApplication.swift
index dd37b45..1ac5a54 100644
--- a/AVRsack/ASApplication.swift
+++ b/AVRsack/ASApplication.swift
@@ -34,6 +34,11 @@ class ASApplication: NSObject, NSApplicationDelegate {
             sketchbooks.append(doc.URLByAppendingPathComponent("AVRSack").path!)
         }
         appDefaults["Sketchbooks"]  = sketchbooks
+        if fileManager.fileExistsAtPath("/usr/local/CrossPack-AVR") {
+            appDefaults["Toolchain"] = "/usr/local/CrossPack-AVR"
+        } else {
+            appDefaults["Toolchain"] = ""
+        }
         
         userDefaults.registerDefaults(appDefaults)
     }
diff --git a/AVRsack/ASPreferences.swift b/AVRsack/ASPreferences.swift
new file mode 100644
index 0000000..c24cc8b
--- /dev/null
+++ b/AVRsack/ASPreferences.swift
@@ -0,0 +1,95 @@
+//
+//  ASPreferences.swift
+//  AVRsack
+//
+//  Created by Matthias Neeracher on 12/10/14.
+//  Copyright © 2014 Aere Perennius. All rights reserved.
+//
+
+import Cocoa
+
+private let kASToolchainCrosspack   = 0
+private let kASToolchainArduino     = 1
+private let kASToolchainOther       = 2
+
+class ASPreferences: NSWindowController, NSOpenSavePanelDelegate {
+     dynamic var toolchainPref : String = "" {
+        didSet(oldPref) {
+            NSUserDefaults.standardUserDefaults().setObject(toolchainPref, forKey: "Toolchain")
+        }
+    }
+    var toolchainType : Int {
+        get {
+            switch toolchainPref {
+            case "/usr/local/CrossPack-AVR":
+                return kASToolchainCrosspack
+            case "":
+                return kASToolchainArduino
+            default:
+                return kASToolchainOther
+            }
+        }
+        
+        set (toolchain) {
+            switch toolchain {
+            case kASToolchainCrosspack:
+                toolchainPref   = "/usr/local/CrossPack-AVR"
+            case kASToolchainArduino:
+                toolchainPref   = ""
+            default:
+                otherToolchainDialog()
+            }
+        }
+    }
+    class func keyPathsForValuesAffectingToolchainType() -> NSSet {
+        return NSSet(objects: "toolchainPref")
+    }
+
+    var toolchainPath : String {
+        get {
+            if toolchainPref != "" {
+                return toolchainPref
+            } else {
+                return NSWorkspace.sharedWorkspace().URLForApplicationWithBundleIdentifier("cc.arduino.Arduino")!.path! +
+                    "/Contents/Resources/Java/hardware/tools/avr"
+            }
+        }
+    }
+    class func keyPathsForValuesAffectingToolchainPath() -> NSSet {
+        return NSSet(objects: "toolchainPref")
+    }
+
+    override convenience init() {
+        self.init(windowNibName:"ASPreferences")
+    }
+    
+    override func awakeFromNib() {
+        super.awakeFromNib()
+        toolchainPref = NSUserDefaults.standardUserDefaults().objectForKey("Toolchain") as String
+    }
+    
+    var hasCrossPackAVR : Bool {
+        get {
+            return NSFileManager.defaultManager().fileExistsAtPath("/usr/local/CrossPack-AVR/bin")
+        }
+    }
+    
+    func otherToolchainDialog() {
+        let openPanel                       = NSOpenPanel()
+        openPanel.delegate                  = self
+        openPanel.canChooseFiles            = false
+        openPanel.canChooseDirectories      = true
+        openPanel.allowsMultipleSelection   = false
+        openPanel.resolvesAliases           = true
+        openPanel.beginSheetModalForWindow(window!, completionHandler: { (returnCode: Int) -> Void in
+            if returnCode == NSFileHandlingPanelOKButton {
+                self.toolchainPref   = openPanel.URL!.path!
+            }
+        })
+    }
+    
+    func panel(sender: AnyObject, shouldEnableURL url: NSURL) -> Bool {
+        let gccPath = url.URLByAppendingPathComponent("bin/avr-gcc")
+        return NSFileManager.defaultManager().fileExistsAtPath(gccPath.path!)
+    }
+}
diff --git a/AVRsack/Base.lproj/ASPreferences.xib b/AVRsack/Base.lproj/ASPreferences.xib
new file mode 100644
index 0000000..7daf5e4
--- /dev/null
+++ b/AVRsack/Base.lproj/ASPreferences.xib
@@ -0,0 +1,108 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="7096" systemVersion="14C82" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+    <dependencies>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="7096"/>
+    </dependencies>
+    <objects>
+        <customObject id="-2" userLabel="File's Owner" customClass="ASPreferences" customModule="AVRsack" customModuleProvider="target">
+            <connections>
+                <outlet property="window" destination="QvC-M9-y7g" id="UPg-mQ-lKM"/>
+            </connections>
+        </customObject>
+        <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
+        <customObject id="-3" userLabel="Application" customClass="NSObject"/>
+        <window title="Preferences" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" oneShot="NO" releasedWhenClosed="NO" showsToolbarButton="NO" visibleAtLaunch="NO" animationBehavior="default" id="QvC-M9-y7g">
+            <windowStyleMask key="styleMask" titled="YES" closable="YES"/>
+            <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
+            <rect key="contentRect" x="196" y="240" width="473" height="230"/>
+            <rect key="screenRect" x="0.0" y="0.0" width="1440" height="877"/>
+            <view key="contentView" id="EiT-Mj-1SZ">
+                <rect key="frame" x="0.0" y="-6" width="473" height="230"/>
+                <autoresizingMask key="autoresizingMask"/>
+                <subviews>
+                    <box autoresizesSubviews="NO" fixedFrame="YES" title="Toolchain" borderType="bezel" translatesAutoresizingMaskIntoConstraints="NO" id="lUB-N9-MQk">
+                        <rect key="frame" x="17" y="85" width="446" height="136"/>
+                        <view key="contentView">
+                            <rect key="frame" x="3" y="3" width="440" height="118"/>
+                            <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                            <subviews>
+                                <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="9aO-EG-pZd">
+                                    <rect key="frame" x="14" y="17" width="412" height="17"/>
+                                    <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Label" id="lLl-0E-bfa">
+                                        <font key="font" metaFont="fixedUser" size="11"/>
+                                        <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
+                                        <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                                    </textFieldCell>
+                                    <connections>
+                                        <binding destination="-2" name="value" keyPath="toolchainPath" id="1bg-4u-IfN"/>
+                                    </connections>
+                                </textField>
+                                <matrix verticalHuggingPriority="750" fixedFrame="YES" allowsEmptySelection="NO" autosizesCells="NO" translatesAutoresizingMaskIntoConstraints="NO" id="I7Q-7e-0fF">
+                                    <rect key="frame" x="17" y="47" width="407" height="62"/>
+                                    <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                                    <size key="cellSize" width="407" height="18"/>
+                                    <size key="intercellSpacing" width="0.0" height="4"/>
+                                    <buttonCell key="prototype" type="radio" title="CrossPack-AVR" bezelStyle="regularSquare" imagePosition="left" alignment="left" inset="2" id="YdD-bN-1zl">
+                                        <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
+                                        <font key="font" metaFont="system"/>
+                                    </buttonCell>
+                                    <cells>
+                                        <column>
+                                            <buttonCell type="radio" title="CrossPack-AVR" bezelStyle="regularSquare" imagePosition="left" alignment="left" inset="2" id="Tup-pR-nsY">
+                                                <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
+                                                <font key="font" metaFont="system"/>
+                                                <connections>
+                                                    <binding destination="-2" name="enabled" keyPath="hasCrossPackAVR" id="0UQ-FH-CMa"/>
+                                                </connections>
+                                            </buttonCell>
+                                            <buttonCell type="radio" title="Arduino" bezelStyle="regularSquare" imagePosition="left" alignment="left" tag="1" inset="2" id="zIW-6Z-Ogk">
+                                                <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
+                                                <font key="font" metaFont="system"/>
+                                            </buttonCell>
+                                            <buttonCell type="radio" title="Other…" bezelStyle="regularSquare" imagePosition="left" alignment="left" tag="2" inset="2" id="fk8-pr-Yac">
+                                                <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
+                                                <font key="font" metaFont="system"/>
+                                            </buttonCell>
+                                        </column>
+                                    </cells>
+                                    <connections>
+                                        <binding destination="-2" name="selectedTag" keyPath="toolchainType" id="l8Q-Gq-AtL"/>
+                                    </connections>
+                                </matrix>
+                            </subviews>
+                        </view>
+                        <color key="borderColor" white="0.0" alpha="0.41999999999999998" colorSpace="calibratedWhite"/>
+                        <color key="fillColor" white="0.0" alpha="0.0" colorSpace="calibratedWhite"/>
+                    </box>
+                    <slider verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="Uao-vY-7Of">
+                        <rect key="frame" x="141" y="41" width="314" height="25"/>
+                        <sliderCell key="cell" state="on" alignment="left" maxValue="4" doubleValue="2" tickMarkPosition="below" numberOfTickMarks="5" allowsTickMarkValuesOnly="YES" sliderType="linear" id="7Y7-kq-HKp"/>
+                        <connections>
+                            <binding destination="U9x-0v-Fkq" name="value" keyPath="values.UploadVerbosity" id="D6L-gh-25Z"/>
+                        </connections>
+                    </slider>
+                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="KJa-Bw-fAb">
+                        <rect key="frame" x="20" y="45" width="117" height="17"/>
+                        <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Upload Verbosity" id="bb7-nI-YMg">
+                            <font key="font" metaFont="system"/>
+                            <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
+                            <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                        </textFieldCell>
+                    </textField>
+                    <button fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="8aR-WB-BsV">
+                        <rect key="frame" x="20" y="18" width="247" height="18"/>
+                        <buttonCell key="cell" type="check" title="Show Source Code in Disassembly" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="n3w-Da-CaD">
+                            <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
+                            <font key="font" metaFont="system"/>
+                        </buttonCell>
+                        <connections>
+                            <binding destination="U9x-0v-Fkq" name="value" keyPath="values.ShowSourceInDisassembly" id="Nnr-C2-5B5"/>
+                        </connections>
+                    </button>
+                </subviews>
+            </view>
+            <point key="canvasLocation" x="338.5" y="245"/>
+        </window>
+        <userDefaultsController representsSharedInstance="YES" id="U9x-0v-Fkq"/>
+    </objects>
+</document>
diff --git a/AVRsack/Base.lproj/MainMenu.xib b/AVRsack/Base.lproj/MainMenu.xib
index 19d0dc6..cd597d4 100644
--- a/AVRsack/Base.lproj/MainMenu.xib
+++ b/AVRsack/Base.lproj/MainMenu.xib
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="7096" systemVersion="14B25" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="7096" systemVersion="14C82" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
     <dependencies>
         <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="7096"/>
     </dependencies>
@@ -18,6 +18,7 @@
             </connections>
         </customObject>
         <customObject id="YLy-65-1bz" customClass="NSFontManager"/>
+        <customObject id="sor-iB-NZD" customClass="ASPreferences" customModule="AVRsack" customModuleProvider="target"/>
         <menu title="Main Menu" systemMenu="main" id="AYu-sK-qS6">
             <items>
                 <menuItem title="AVRsack" id="1Xt-HY-uBw">
@@ -31,7 +32,11 @@
                                 </connections>
                             </menuItem>
                             <menuItem isSeparatorItem="YES" id="VOq-y0-SEH"/>
-                            <menuItem title="Preferences…" keyEquivalent="," id="BOF-NM-1cW"/>
+                            <menuItem title="Preferences…" keyEquivalent="," id="BOF-NM-1cW">
+                                <connections>
+                                    <action selector="showWindow:" target="sor-iB-NZD" id="zLp-gD-hKn"/>
+                                </connections>
+                            </menuItem>
                             <menuItem isSeparatorItem="YES" id="wFC-TO-SCJ"/>
                             <menuItem title="Services" id="NMo-om-nkz">
                                 <modifierMask key="keyEquivalentModifierMask"/>
diff --git a/AVRsack/Defaults.plist b/AVRsack/Defaults.plist
index 585e59e..f963774 100644
--- a/AVRsack/Defaults.plist
+++ b/AVRsack/Defaults.plist
@@ -2,6 +2,10 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
+	<key>ShowSourceInDisassembly</key>
+	<string></string>
+	<key>UploadVerbosity</key>
+	<integer>2</integer>
 	<key>RecentProgrammers</key>
 	<array>
 		<string>usbasp</string>