diff --git a/src/core/justifier.cpp b/src/core/justifier.cpp
index 211b394c7..dd91644cd 100644
--- a/src/core/justifier.cpp
+++ b/src/core/justifier.cpp
@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2019-2024 Connor McLaughlin <stenzek@gmail.com>
+// SPDX-FileCopyrightText: 2019-2025 Connor McLaughlin <stenzek@gmail.com>
 // SPDX-License-Identifier: CC-BY-NC-ND-4.0
 
 #include "justifier.h"
@@ -89,6 +89,7 @@ bool Justifier::DoState(StateWrapper& sw, bool apply_input_state)
     m_position_valid = position_valid;
   }
 
+  sw.DoEx(&m_irq_enabled, 82, true);
   sw.Do(&m_transfer_state);
 
   if (sw.IsReading())
@@ -178,6 +179,13 @@ bool Justifier::Transfer(const u8 data_in, u8* data_out)
 
     case TransferState::ButtonsLSB:
     {
+      const bool new_irq_enabled = ((data_in & 0x10) == 0x10);
+      if (new_irq_enabled != m_irq_enabled)
+      {
+        m_irq_enabled = new_irq_enabled;
+        UpdateIRQEvent();
+      }
+
       *data_out = Truncate8(m_button_state);
       m_transfer_state = TransferState::ButtonsMSB;
       return true;
@@ -251,7 +259,7 @@ void Justifier::UpdateIRQEvent()
   // TODO: Avoid deactivate and event sort.
   m_irq_event.Deactivate();
 
-  if (!m_position_valid)
+  if (!m_position_valid || !m_irq_enabled)
     return;
 
   u32 current_tick, current_line;
diff --git a/src/core/justifier.h b/src/core/justifier.h
index 27de367d8..05ad8953b 100644
--- a/src/core/justifier.h
+++ b/src/core/justifier.h
@@ -94,6 +94,7 @@ private:
   u16 m_button_state = UINT16_C(0xFFFF);
   u8 m_shoot_offscreen = 0;
   bool m_position_valid = false;
+  bool m_irq_enabled = false;
 
   TransferState m_transfer_state = TransferState::Idle;
 
diff --git a/src/core/save_state_version.h b/src/core/save_state_version.h
index 103ab4f01..36ed7393b 100644
--- a/src/core/save_state_version.h
+++ b/src/core/save_state_version.h
@@ -6,7 +6,7 @@
 #include "common/types.h"
 
 static constexpr u32 SAVE_STATE_MAGIC = 0x43435544;
-static constexpr u32 SAVE_STATE_VERSION = 81;
+static constexpr u32 SAVE_STATE_VERSION = 82;
 static constexpr u32 SAVE_STATE_MINIMUM_VERSION = 42;
 
 static_assert(SAVE_STATE_VERSION >= SAVE_STATE_MINIMUM_VERSION);