diff --git a/src/main/scala/li/cil/oc/common/block/Microcontroller.scala b/src/main/scala/li/cil/oc/common/block/Microcontroller.scala
index 7397115b3..c4c475bcd 100644
--- a/src/main/scala/li/cil/oc/common/block/Microcontroller.scala
+++ b/src/main/scala/li/cil/oc/common/block/Microcontroller.scala
@@ -3,6 +3,7 @@ package li.cil.oc.common.block
 import java.util
 
 import li.cil.oc.Settings
+import li.cil.oc.api
 import li.cil.oc.client.KeyBindings
 import li.cil.oc.common.Tier
 import li.cil.oc.common.item.data.MicrocontrollerData
@@ -10,6 +11,7 @@ import li.cil.oc.common.tileentity
 import li.cil.oc.integration.util.NEI
 import li.cil.oc.integration.util.Wrench
 import li.cil.oc.util.BlockPosition
+import li.cil.oc.util.InventoryUtils
 import li.cil.oc.util.Rarity
 import net.minecraft.entity.EntityLivingBase
 import net.minecraft.entity.player.EntityPlayer
@@ -68,16 +70,32 @@ class Microcontroller(protected implicit val tileTag: ClassTag[tileentity.Microc
 
   override def onBlockActivated(world: World, x: Int, y: Int, z: Int, player: EntityPlayer,
                                 side: ForgeDirection, hitX: Float, hitY: Float, hitZ: Float) = {
-    if (!player.isSneaking && !Wrench.holdsApplicableWrench(player, BlockPosition(x, y, z))) {
-      if (!world.isRemote) {
-        world.getTileEntity(x, y, z) match {
-          case mcu: tileentity.Microcontroller =>
-            if (mcu.machine.isRunning) mcu.machine.stop()
-            else mcu.machine.start()
-          case _ =>
+    if (!Wrench.holdsApplicableWrench(player, BlockPosition(x, y, z))) {
+      if (!player.isSneaking) {
+        if (!world.isRemote) {
+          world.getTileEntity(x, y, z) match {
+            case mcu: tileentity.Microcontroller =>
+              if (mcu.machine.isRunning) mcu.machine.stop()
+              else mcu.machine.start()
+            case _ =>
+          }
         }
+        true
       }
-      true
+      else if (api.Items.get(player.getHeldItem) == api.Items.get("eeprom")) {
+        if (!world.isRemote) {
+          world.getTileEntity(x, y, z) match {
+            case mcu: tileentity.Microcontroller =>
+              val newEeprom = player.inventory.decrStackSize(player.inventory.currentItem, 1)
+              mcu.changeEEPROM(newEeprom) match {
+                case Some(oldEeprom) => InventoryUtils.addToPlayerInventory(oldEeprom, player)
+                case _ =>
+              }
+          }
+        }
+        true
+      }
+      else false
     }
     else false
   }
diff --git a/src/main/scala/li/cil/oc/common/item/EEPROM.scala b/src/main/scala/li/cil/oc/common/item/EEPROM.scala
index e9959db44..1e3d5dc89 100644
--- a/src/main/scala/li/cil/oc/common/item/EEPROM.scala
+++ b/src/main/scala/li/cil/oc/common/item/EEPROM.scala
@@ -1,9 +1,13 @@
 package li.cil.oc.common.item
 
 import li.cil.oc.Settings
+import net.minecraft.entity.player.EntityPlayer
 import net.minecraft.item.ItemStack
+import net.minecraft.world.World
 
 class EEPROM extends SimpleItem {
+  override def doesSneakBypassUse(world: World, x: Int, y: Int, z: Int, player: EntityPlayer): Boolean = true
+
   override def getItemStackDisplayName(stack: ItemStack): String = {
     if (stack.hasTagCompound) {
       val tag = stack.getTagCompound
diff --git a/src/main/scala/li/cil/oc/common/item/data/MicrocontrollerData.scala b/src/main/scala/li/cil/oc/common/item/data/MicrocontrollerData.scala
index a8657920f..b61ec4aba 100644
--- a/src/main/scala/li/cil/oc/common/item/data/MicrocontrollerData.scala
+++ b/src/main/scala/li/cil/oc/common/item/data/MicrocontrollerData.scala
@@ -17,20 +17,26 @@ class MicrocontrollerData extends ItemData {
 
   var tier = Tier.One
 
-  var components = Array.empty[ItemStack]
+  var components = Array[ItemStack](null)
 
   var storedEnergy = 0
 
   override def load(nbt: NBTTagCompound) {
     tier = nbt.getByte(Settings.namespace + "tier")
     components = nbt.getTagList(Settings.namespace + "components", NBT.TAG_COMPOUND).
-      toArray[NBTTagCompound].map(ItemUtils.loadStack)
+      toArray[NBTTagCompound].map(ItemUtils.loadStack).filter(_ != null)
     storedEnergy = nbt.getInteger(Settings.namespace + "storedEnergy")
+
+    // Reserve slot for EEPROM if necessary, avoids having to resize the
+    // components array in the MCU tile entity, which isn't possible currently.
+    if (!components.exists(stack => api.Items.get(stack) == api.Items.get("eeprom"))) {
+      components :+= null
+    }
   }
 
   override def save(nbt: NBTTagCompound) {
     nbt.setByte(Settings.namespace + "tier", tier.toByte)
-    nbt.setNewTagList(Settings.namespace + "components", components.toIterable)
+    nbt.setNewTagList(Settings.namespace + "components", components.filter(_ != null).toIterable)
     nbt.setInteger(Settings.namespace + "storedEnergy", storedEnergy)
   }
 
diff --git a/src/main/scala/li/cil/oc/common/tileentity/Microcontroller.scala b/src/main/scala/li/cil/oc/common/tileentity/Microcontroller.scala
index b33b7ae67..3e5efb0a6 100644
--- a/src/main/scala/li/cil/oc/common/tileentity/Microcontroller.scala
+++ b/src/main/scala/li/cil/oc/common/tileentity/Microcontroller.scala
@@ -221,7 +221,9 @@ class Microcontroller extends traits.PowerAcceptor with traits.Hub with traits.C
     nbt.setNewCompoundTag("info", info.save)
   }
 
-  override lazy val items = info.components.map(Option(_))
+  override def items = info.components.map(Option(_))
+
+  override def updateItems(slot: Int, stack: ItemStack): Unit = info.components(slot) = stack
 
   override def getSizeInventory = info.components.length
 
@@ -232,4 +234,19 @@ class Microcontroller extends traits.PowerAcceptor with traits.Hub with traits.C
 
   // Nope.
   override def decrStackSize(slot: Int, amount: Int) = null
+
+  // For hotswapping EEPROMs.
+  def changeEEPROM(newEeprom: ItemStack) = {
+    val oldEepromIndex = info.components.indexWhere(api.Items.get(_) == api.Items.get("eeprom"))
+    if (oldEepromIndex >= 0) {
+      val oldEeprom = info.components(oldEepromIndex)
+      super.setInventorySlotContents(oldEepromIndex, newEeprom)
+      Some(oldEeprom)
+    }
+    else {
+      assert(info.components(getSizeInventory - 1) == null)
+      super.setInventorySlotContents(getSizeInventory - 1, newEeprom)
+      None
+    }
+  }
 }