diff --git a/src/main/resources/reference.conf b/src/main/resources/reference.conf
index f59a1280c..42f9df5d7 100644
--- a/src/main/resources/reference.conf
+++ b/src/main/resources/reference.conf
@@ -186,6 +186,11 @@ opencomputers {
       # always be erased when the computer is completely powered off, even if
       # it crashed. This setting is purely for software-triggered reboots.
       eraseTmpOnReboot: false
+
+      # Forces the use of the LuaJ fallback instead of the native libraries.
+      # Use this if you have (unfounded) concerns using native libraries or
+      # experience issues with the native library. Also used for debugging.
+      forceLuaJ: false
   }
 
   # Robot related settings, what they may do and general balancing.
diff --git a/src/main/scala/li/cil/oc/Settings.scala b/src/main/scala/li/cil/oc/Settings.scala
index e488884c7..94687adb4 100644
--- a/src/main/scala/li/cil/oc/Settings.scala
+++ b/src/main/scala/li/cil/oc/Settings.scala
@@ -59,6 +59,7 @@ class Settings(config: Config) {
   val allowBytecode = config.getBoolean("computer.allowBytecode")
   val logLuaCallbackErrors = config.getBoolean("computer.logCallbackErrors")
   val eraseTmpOnReboot = config.getBoolean("computer.eraseTmpOnReboot")
+  val forceLuaJ = config.getBoolean("computer.forceLuaJ")
 
   // ----------------------------------------------------------------------- //
   // robot
diff --git a/src/main/scala/li/cil/oc/common/Proxy.scala b/src/main/scala/li/cil/oc/common/Proxy.scala
index 17ad2e66f..d81679730 100644
--- a/src/main/scala/li/cil/oc/common/Proxy.scala
+++ b/src/main/scala/li/cil/oc/common/Proxy.scala
@@ -44,7 +44,7 @@ class Proxy {
     api.Items.instance = Items
     api.Machine.instance = machine.Machine
     api.Machine.LuaArchitecture =
-      if (LuaStateFactory.isAvailable) classOf[NativeLuaArchitecture]
+      if (LuaStateFactory.isAvailable && !Settings.get.forceLuaJ) classOf[NativeLuaArchitecture]
       else classOf[LuaJLuaArchitecture]
     api.Network.instance = network.Network
 
diff --git a/src/main/scala/li/cil/oc/server/component/machine/LuaJLuaArchitecture.scala b/src/main/scala/li/cil/oc/server/component/machine/LuaJLuaArchitecture.scala
index 5f710a43a..26124348d 100644
--- a/src/main/scala/li/cil/oc/server/component/machine/LuaJLuaArchitecture.scala
+++ b/src/main/scala/li/cil/oc/server/component/machine/LuaJLuaArchitecture.scala
@@ -25,11 +25,14 @@ class LuaJLuaArchitecture(val machine: api.machine.Machine) extends Architecture
 
   private[machine] var memory = 0
 
+  private[machine] var bootAddress = ""
+
   private val apis = Array(
     new ComponentAPI(this),
     new ComputerAPI(this),
     new OSAPI(this),
     new SystemAPI(this),
+    new UnicodeAPI(this),
     new UserdataAPI(this))
 
   private[machine] def invoke(f: () => Array[AnyRef]): Varargs = try {
@@ -158,16 +161,18 @@ class LuaJLuaArchitecture(val machine: api.machine.Machine) extends Architecture
       // The kernel thread returned. If it threw we'd be in the catch below.
       else {
         // We're expecting the result of a pcall, if anything, so boolean + (result | string).
-        if (results.`type`(2) != LuaValue.TBOOLEAN || !(results.isstring(3) || results.isnil(3))) {
+        if (results.`type`(2) != LuaValue.TBOOLEAN || !(results.isstring(3) || results.isnoneornil(3))) {
           OpenComputers.log.warning("Kernel returned unexpected results.")
         }
         // The pcall *should* never return normally... but check for it nonetheless.
-        if (results.toboolean(1)) {
+        if (results.toboolean(2)) {
           OpenComputers.log.warning("Kernel stopped unexpectedly.")
           new ExecutionResult.Shutdown(false)
         }
         else {
-          val error = results.tojstring(3)
+          val error =
+            if (results.isuserdata(3)) results.touserdata(3).toString
+            else results.tojstring(3)
           if (error != null) new ExecutionResult.Error(error)
           else new ExecutionResult.Error("unknown error")
         }
@@ -219,6 +224,8 @@ class LuaJLuaArchitecture(val machine: api.machine.Machine) extends Architecture
   // ----------------------------------------------------------------------- //
 
   override def load(nbt: NBTTagCompound) {
+    bootAddress = nbt.getString("bootAddress")
+
     if (machine.isRunning) {
       machine.stop()
       machine.start()
@@ -226,5 +233,8 @@ class LuaJLuaArchitecture(val machine: api.machine.Machine) extends Architecture
   }
 
   override def save(nbt: NBTTagCompound) {
+    if (bootAddress != null) {
+      nbt.setString("bootAddress", bootAddress)
+    }
   }
 }
diff --git a/src/main/scala/li/cil/oc/server/component/machine/NativeLuaArchitecture.scala b/src/main/scala/li/cil/oc/server/component/machine/NativeLuaArchitecture.scala
index ded56c816..9f7aad7bc 100644
--- a/src/main/scala/li/cil/oc/server/component/machine/NativeLuaArchitecture.scala
+++ b/src/main/scala/li/cil/oc/server/component/machine/NativeLuaArchitecture.scala
@@ -316,6 +316,8 @@ class NativeLuaArchitecture(val machine: api.machine.Machine) extends Architectu
   private def state = machine.asInstanceOf[Machine].state
 
   override def load(nbt: NBTTagCompound) {
+    bootAddress = nbt.getString("bootAddress")
+
     // Unlimit memory use while unpersisting.
     lua.setTotalMemory(Integer.MAX_VALUE)
 
@@ -366,6 +368,10 @@ class NativeLuaArchitecture(val machine: api.machine.Machine) extends Architectu
   }
 
   override def save(nbt: NBTTagCompound) {
+    if (bootAddress != null) {
+      nbt.setString("bootAddress", bootAddress)
+    }
+
     // Unlimit memory while persisting.
     lua.setTotalMemory(Integer.MAX_VALUE)
 
diff --git a/src/main/scala/li/cil/oc/server/component/machine/luaj/ComputerAPI.scala b/src/main/scala/li/cil/oc/server/component/machine/luaj/ComputerAPI.scala
index 24267dadf..ff2634d1b 100644
--- a/src/main/scala/li/cil/oc/server/component/machine/luaj/ComputerAPI.scala
+++ b/src/main/scala/li/cil/oc/server/component/machine/luaj/ComputerAPI.scala
@@ -27,6 +27,18 @@ class ComputerAPI(owner: LuaJLuaArchitecture) extends LuaJAPI(owner) {
       case _ => LuaValue.NIL
     })
 
+    // Get/set address of boot device.
+    computer.set("getBootAddress", (_: Varargs) => owner.bootAddress match {
+      case "" => LuaValue.NIL
+      case address => LuaValue.valueOf(address)
+    })
+
+    computer.set("setBootAddress", (args: Varargs) => {
+      if (args.isnoneornil(1)) owner.bootAddress = ""
+      else owner.bootAddress = args.checkjstring(1)
+      LuaValue.NIL
+    })
+
     computer.set("freeMemory", (_: Varargs) => LuaValue.valueOf(owner.memory / 2))
 
     computer.set("totalMemory", (_: Varargs) => LuaValue.valueOf(owner.memory))
diff --git a/src/main/scala/li/cil/oc/server/component/machine/luaj/SystemAPI.scala b/src/main/scala/li/cil/oc/server/component/machine/luaj/SystemAPI.scala
index 2eb08097e..45526f48d 100644
--- a/src/main/scala/li/cil/oc/server/component/machine/luaj/SystemAPI.scala
+++ b/src/main/scala/li/cil/oc/server/component/machine/luaj/SystemAPI.scala
@@ -13,7 +13,7 @@ class SystemAPI(owner: LuaJLuaArchitecture) extends LuaJAPI(owner) {
     system.set("allowBytecode", (_: Varargs) => LuaValue.valueOf(Settings.get.allowBytecode))
 
     // How long programs may run without yielding before we stop them.
-    system.set("timeout", LuaValue.valueOf(Settings.get.timeout))
+    system.set("timeout", (_: Varargs) => LuaValue.valueOf(Settings.get.timeout))
 
     lua.set("system", system)
   }
diff --git a/src/main/scala/li/cil/oc/util/ScalaClosure.scala b/src/main/scala/li/cil/oc/util/ScalaClosure.scala
index 2e96b5c8a..07358b640 100644
--- a/src/main/scala/li/cil/oc/util/ScalaClosure.scala
+++ b/src/main/scala/li/cil/oc/util/ScalaClosure.scala
@@ -8,6 +8,7 @@ import scala.collection.mutable
 import scala.language.implicitConversions
 import scala.math.ScalaNumber
 import scala.runtime.BoxedUnit
+import li.cil.oc.api.machine.Value
 
 class ScalaClosure(val f: (Varargs) => Varargs) extends VarArgFunction {
   override def invoke(args: Varargs) = f(args)
@@ -41,6 +42,7 @@ object ScalaClosure {
       case value: java.lang.String => LuaValue.valueOf(value)
       case value: Array[Byte] => LuaValue.valueOf(value)
       case value: Array[_] => toLuaList(value)
+      case value: Value => LuaValue.userdataOf(value)
       case value: Product => toLuaList(value.productIterator.toIterable)
       case value: Seq[_] => toLuaList(value)
       case value: java.util.Map[_, _] => toLuaTable(value.toMap)