diff --git a/src/main/java/li/cil/oc2/client/gui/ComputerContainerScreen.java b/src/main/java/li/cil/oc2/client/gui/ComputerContainerScreen.java
index 8149db32..b61aba40 100644
--- a/src/main/java/li/cil/oc2/client/gui/ComputerContainerScreen.java
+++ b/src/main/java/li/cil/oc2/client/gui/ComputerContainerScreen.java
@@ -5,11 +5,13 @@ import com.mojang.blaze3d.systems.RenderSystem;
 import li.cil.oc2.api.API;
 import li.cil.oc2.api.bus.device.DeviceTypes;
 import li.cil.oc2.client.gui.util.GuiUtils;
+import li.cil.oc2.common.Constants;
 import li.cil.oc2.common.container.ComputerContainer;
 import net.minecraft.client.gui.screen.inventory.ContainerScreen;
 import net.minecraft.entity.player.PlayerInventory;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.util.text.ITextComponent;
+import net.minecraft.util.text.TranslationTextComponent;
 
 import static java.util.Objects.requireNonNull;
 
@@ -35,6 +37,10 @@ public final class ComputerContainerScreen extends ContainerScreen<ComputerConta
         GuiUtils.renderMissingDeviceInfoIcon(matrixStack, this, DeviceTypes.MEMORY, GuiUtils.WARN_ICON);
         GuiUtils.renderMissingDeviceInfoIcon(matrixStack, this, DeviceTypes.HARD_DRIVE, GuiUtils.INFO_ICON);
 
+        GuiUtils.renderMissingDeviceInfoTooltip(matrixStack, this, mouseX, mouseY, DeviceTypes.FLASH_MEMORY, new TranslationTextComponent(Constants.TOOLTIP_FLASH_MEMORY_MISSING));
+        GuiUtils.renderMissingDeviceInfoTooltip(matrixStack, this, mouseX, mouseY, DeviceTypes.MEMORY, new TranslationTextComponent(Constants.TOOLTIP_MEMORY_MISSING));
+        GuiUtils.renderMissingDeviceInfoTooltip(matrixStack, this, mouseX, mouseY, DeviceTypes.HARD_DRIVE, new TranslationTextComponent(Constants.TOOLTIP_HARD_DRIVE_MISSING));
+
         renderHoveredTooltip(matrixStack, mouseX, mouseY);
     }
 
diff --git a/src/main/java/li/cil/oc2/client/gui/RobotContainerScreen.java b/src/main/java/li/cil/oc2/client/gui/RobotContainerScreen.java
index 40090673..305e15c3 100644
--- a/src/main/java/li/cil/oc2/client/gui/RobotContainerScreen.java
+++ b/src/main/java/li/cil/oc2/client/gui/RobotContainerScreen.java
@@ -5,12 +5,14 @@ import com.mojang.blaze3d.systems.RenderSystem;
 import li.cil.oc2.api.API;
 import li.cil.oc2.api.bus.device.DeviceTypes;
 import li.cil.oc2.client.gui.util.GuiUtils;
+import li.cil.oc2.common.Constants;
 import li.cil.oc2.common.container.RobotContainer;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.screen.inventory.ContainerScreen;
 import net.minecraft.entity.player.PlayerInventory;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.util.text.ITextComponent;
+import net.minecraft.util.text.TranslationTextComponent;
 
 public final class RobotContainerScreen extends ContainerScreen<RobotContainer> {
     private static final ResourceLocation BACKGROUND = new ResourceLocation(API.MOD_ID, "textures/gui/container/robot.png");
@@ -51,6 +53,10 @@ public final class RobotContainerScreen extends ContainerScreen<RobotContainer>
         GuiUtils.renderMissingDeviceInfoIcon(matrixStack, this, DeviceTypes.MEMORY, GuiUtils.WARN_ICON);
         GuiUtils.renderMissingDeviceInfoIcon(matrixStack, this, DeviceTypes.HARD_DRIVE, GuiUtils.INFO_ICON);
 
+        GuiUtils.renderMissingDeviceInfoTooltip(matrixStack, this, mouseX, mouseY, DeviceTypes.FLASH_MEMORY, new TranslationTextComponent(Constants.TOOLTIP_FLASH_MEMORY_MISSING));
+        GuiUtils.renderMissingDeviceInfoTooltip(matrixStack, this, mouseX, mouseY, DeviceTypes.MEMORY, new TranslationTextComponent(Constants.TOOLTIP_MEMORY_MISSING));
+        GuiUtils.renderMissingDeviceInfoTooltip(matrixStack, this, mouseX, mouseY, DeviceTypes.HARD_DRIVE, new TranslationTextComponent(Constants.TOOLTIP_HARD_DRIVE_MISSING));
+
         renderHoveredTooltip(matrixStack, mouseX, mouseY);
     }
 
diff --git a/src/main/java/li/cil/oc2/client/gui/util/GuiUtils.java b/src/main/java/li/cil/oc2/client/gui/util/GuiUtils.java
index 8cba14dd..ca15e8d8 100644
--- a/src/main/java/li/cil/oc2/client/gui/util/GuiUtils.java
+++ b/src/main/java/li/cil/oc2/client/gui/util/GuiUtils.java
@@ -9,6 +9,7 @@ import net.minecraft.client.gui.screen.inventory.ContainerScreen;
 import net.minecraft.inventory.container.Container;
 import net.minecraft.inventory.container.Slot;
 import net.minecraft.util.ResourceLocation;
+import net.minecraft.util.text.ITextComponent;
 
 import java.util.Optional;
 
@@ -36,6 +37,24 @@ public final class GuiUtils {
         });
     }
 
+    public static <TContainer extends Container> void renderMissingDeviceInfoTooltip(final MatrixStack matrixStack, final ContainerScreen<TContainer> screen, final int mouseX, final int mouseY, final DeviceType type, final ITextComponent tooltip) {
+        final boolean isCursorHoldingStack = !screen.getMinecraft().player.inventory.getItemStack().isEmpty();
+        if (isCursorHoldingStack) {
+            return;
+        }
+
+        final Slot hoveredSlot = screen.getSlotUnderMouse();
+        if (hoveredSlot != null && hoveredSlot.getHasStack()) {
+            return;
+        }
+
+        findFirstSlotOfTypeIfAllSlotsOfTypeEmpty(screen.getContainer(), type).ifPresent(slot -> {
+            if (slot == hoveredSlot) {
+                screen.renderTooltip(matrixStack, tooltip, mouseX, mouseY);
+            }
+        });
+    }
+
     private static Optional<TypedSlotItemHandler> findFirstSlotOfTypeIfAllSlotsOfTypeEmpty(final Container container, final DeviceType type) {
         TypedSlotItemHandler firstSlot = null;
         for (final Slot slot : container.inventorySlots) {
diff --git a/src/main/java/li/cil/oc2/common/Constants.java b/src/main/java/li/cil/oc2/common/Constants.java
index d31e4312..4256bf27 100644
--- a/src/main/java/li/cil/oc2/common/Constants.java
+++ b/src/main/java/li/cil/oc2/common/Constants.java
@@ -50,6 +50,9 @@ public final class Constants {
 
     public static final String TOOLTIP_DESCRIPTION_SUFFIX = ".desc";
     public static final String TOOLTIP_DEVICE_NEEDS_REBOOT = "tooltip.oc2.device_needs_reboot";
+    public static final String TOOLTIP_FLASH_MEMORY_MISSING = "tooltip.oc2.flash_memory_missing";
+    public static final String TOOLTIP_MEMORY_MISSING = "tooltip.oc2.memory_missing";
+    public static final String TOOLTIP_HARD_DRIVE_MISSING = "tooltip.oc2.hard_drive_missing";
 
     ///////////////////////////////////////////////////////////////////
 
diff --git a/src/main/resources/assets/oc2/lang/en_us.json b/src/main/resources/assets/oc2/lang/en_us.json
index f8f98092..168425f9 100644
--- a/src/main/resources/assets/oc2/lang/en_us.json
+++ b/src/main/resources/assets/oc2/lang/en_us.json
@@ -58,5 +58,8 @@
   "message.oc2.connector.error.too_far": "Distance between connectors is too large.",
   "message.oc2.connector.error.obstructed": "No clear line of sight between connectors.",
 
-  "tooltip.oc2.device_needs_reboot": "Requires reboot"
+  "tooltip.oc2.device_needs_reboot": "Requires reboot",
+  "tooltip.oc2.flash_memory_missing": "A flash memory containing a firmware is required to boot.",
+  "tooltip.oc2.memory_missing": "Some memory is required to load the flash memory for execution to boot.",
+  "tooltip.oc2.hard_drive_missing": "Most systems will require a root file system to boot."
 }
\ No newline at end of file