diff --git a/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp b/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
index c686930383..b8d3b8e5a2 100644
--- a/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
+++ b/Source/Core/Core/HW/DSPHLE/DSPHLE.cpp
@@ -67,7 +67,7 @@ void DSPHLE::SendMailToDSP(u32 mail)
 
 void DSPHLE::SetUCode(u32 crc)
 {
-  m_mail_handler.Clear();
+  m_mail_handler.ClearPending();
   m_ucode = UCodeFactory(crc, this, m_wii);
   m_ucode->Initialize();
 }
@@ -77,7 +77,7 @@ void DSPHLE::SetUCode(u32 crc)
 // Even callers are deleted.
 void DSPHLE::SwapUCode(u32 crc)
 {
-  m_mail_handler.Clear();
+  m_mail_handler.ClearPending();
 
   if (m_last_ucode && UCodeInterface::GetCRC(m_last_ucode.get()) == crc)
   {
@@ -196,6 +196,7 @@ u16 DSPHLE::DSP_WriteControlRegister(u16 value)
   {
     INFO_LOG_FMT(DSPHLE, "DSP_CONTROL halt bit changed: {:04x} -> {:04x}", m_dsp_control.Hex,
                  value);
+    m_mail_handler.SetHalted(temp.DSPHalt);
   }
 
   if (temp.DSPReset)
diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
index ce6b8f8a1a..f297b6f53c 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.cpp
@@ -3,8 +3,6 @@
 
 #include "Core/HW/DSPHLE/MailHandler.h"
 
-#include <queue>
-
 #include "Common/ChunkFile.h"
 #include "Common/CommonTypes.h"
 #include "Common/Logging/Log.h"
@@ -19,117 +17,75 @@ CMailHandler::CMailHandler()
 
 CMailHandler::~CMailHandler()
 {
-  Clear();
 }
 
 void CMailHandler::PushMail(u32 mail, bool interrupt, int cycles_into_future)
 {
   if (interrupt)
   {
-    if (m_Mails.empty())
+    if (m_pending_mails.empty())
     {
       DSP::GenerateDSPInterruptFromDSPEmu(DSP::INT_DSP, cycles_into_future);
     }
     else
     {
-      m_Mails.front().second = true;
+      m_pending_mails.front().second = true;
     }
   }
-  m_Mails.emplace(mail, false);
+  m_pending_mails.emplace_back(mail, false);
   DEBUG_LOG_FMT(DSP_MAIL, "DSP writes {:#010x}", mail);
 }
 
 u16 CMailHandler::ReadDSPMailboxHigh()
 {
-  // check if we have a mail for the core
-  if (!m_Mails.empty())
+  // check if we have a mail for the CPU core
+  if (!m_halted && !m_pending_mails.empty())
   {
-    u16 result = (m_Mails.front().first >> 16) & 0xFFFF;
-    return result;
+    m_last_mail = m_pending_mails.front().first;
   }
-  return 0x00;
+  return u16(m_last_mail >> 0x10);
 }
 
 u16 CMailHandler::ReadDSPMailboxLow()
 {
-  // check if we have a mail for the core
-  if (!m_Mails.empty())
+  // check if we have a mail for the CPU core
+  if (!m_halted && !m_pending_mails.empty())
   {
-    u16 result = m_Mails.front().first & 0xFFFF;
-    bool generate_interrupt = m_Mails.front().second;
-    m_Mails.pop();
+    m_last_mail = m_pending_mails.front().first;
+    const bool generate_interrupt = m_pending_mails.front().second;
+
+    m_pending_mails.pop_front();
 
     if (generate_interrupt)
     {
       DSP::GenerateDSPInterruptFromDSPEmu(DSP::INT_DSP);
     }
-
-    return result;
   }
-  return 0x00;
+  // Clear the top bit of the high mail word after the mail has been read.
+  // The remaining bits read back the same as the previous mail, until new mail sent.
+  // (The CPU reads the high word first, and then the low word; since this function returns the low
+  // word, this means that the next read of the high word will have the top bit cleared.)
+  m_last_mail &= ~0x8000'0000;
+  return u16(m_last_mail & 0xffff);
 }
 
-void CMailHandler::Clear()
+void CMailHandler::ClearPending()
 {
-  while (!m_Mails.empty())
-    m_Mails.pop();
+  m_pending_mails.clear();
 }
 
-bool CMailHandler::IsEmpty() const
+bool CMailHandler::HasPending() const
 {
-  return m_Mails.empty();
+  return !m_pending_mails.empty();
 }
 
-void CMailHandler::Halt(bool _Halt)
+void CMailHandler::SetHalted(bool halt)
 {
-  if (_Halt)
-  {
-    Clear();
-    PushMail(0x80544348);
-  }
+  m_halted = halt;
 }
 
 void CMailHandler::DoState(PointerWrap& p)
 {
-  if (p.IsReadMode())
-  {
-    Clear();
-    int sz = 0;
-    p.Do(sz);
-    for (int i = 0; i < sz; i++)
-    {
-      u32 mail = 0;
-      bool interrupt = false;
-      p.Do(mail);
-      p.Do(interrupt);
-      m_Mails.emplace(mail, interrupt);
-    }
-  }
-  else  // WRITE and MEASURE
-  {
-    std::queue<std::pair<u32, bool>> temp;
-    int sz = (int)m_Mails.size();
-    p.Do(sz);
-    for (int i = 0; i < sz; i++)
-    {
-      u32 value = m_Mails.front().first;
-      bool interrupt = m_Mails.front().second;
-      m_Mails.pop();
-      p.Do(value);
-      p.Do(interrupt);
-      temp.emplace(value, interrupt);
-    }
-    if (!m_Mails.empty())
-      PanicAlertFmt("CMailHandler::DoState - WTF?");
-
-    // Restore queue.
-    for (int i = 0; i < sz; i++)
-    {
-      u32 value = temp.front().first;
-      bool interrupt = temp.front().second;
-      temp.pop();
-      m_Mails.emplace(value, interrupt);
-    }
-  }
+  p.Do(m_pending_mails);
 }
 }  // namespace DSP::HLE
diff --git a/Source/Core/Core/HW/DSPHLE/MailHandler.h b/Source/Core/Core/HW/DSPHLE/MailHandler.h
index e5afbc9869..ee38bcde53 100644
--- a/Source/Core/Core/HW/DSPHLE/MailHandler.h
+++ b/Source/Core/Core/HW/DSPHLE/MailHandler.h
@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include <queue>
+#include <deque>
 #include <utility>
 
 #include "Common/CommonTypes.h"
@@ -20,16 +20,29 @@ public:
 
   // TODO: figure out correct timing for interrupts rather than defaulting to "immediately."
   void PushMail(u32 mail, bool interrupt = false, int cycles_into_future = 0);
-  void Clear();
-  void Halt(bool _Halt);
+  void SetHalted(bool halt);
   void DoState(PointerWrap& p);
-  bool IsEmpty() const;
+  bool HasPending() const;
+
+  // Clear any pending mail from the current uCode.  This is called by DSPHLE::SetUCode and
+  // DSPHLE::SwapUCode. Since pending mail is an abstraction for DSPHLE and not something that
+  // actually exists on real hardware, HLE implementations do not need to call this directly.
+  // Note that this function does not reset m_last_mail, which will continue to read the same value
+  // until the new uCode sends mail.
+  void ClearPending();
 
   u16 ReadDSPMailboxHigh();
   u16 ReadDSPMailboxLow();
 
 private:
-  // mail handler
-  std::queue<std::pair<u32, bool>> m_Mails;
+  // The actual DSP only has a single pair of mail registers, and doesn't keep track of pending
+  // mails. But for HLE, it's a lot easier to write all the mails that will be read ahead of time,
+  // and then give them to the CPU in the requested order.
+  std::deque<std::pair<u32, bool>> m_pending_mails;
+  // If no pending mail exists, the last mail that was read is returned,
+  // but with the top bit (0x80000000) cleared.
+  u32 m_last_mail = 0;
+  // When halted, the DSP itself is not running, but the last mail can be read.
+  bool m_halted = false;
 };
 }  // namespace DSP::HLE
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
index ee64a96659..c53d7a8e8e 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
@@ -32,11 +32,6 @@ AXUCode::AXUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
   INFO_LOG_FMT(DSPHLE, "Instantiating AXUCode: crc={:08x}", crc);
 }
 
-AXUCode::~AXUCode()
-{
-  m_mail_handler.Clear();
-}
-
 void AXUCode::Initialize()
 {
   m_mail_handler.PushMail(DSP_INIT, true);
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AX.h b/Source/Core/Core/HW/DSPHLE/UCodes/AX.h
index 4755002521..d95d2db27f 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AX.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AX.h
@@ -66,7 +66,6 @@ class AXUCode : public UCodeInterface
 {
 public:
   AXUCode(DSPHLE* dsphle, u32 crc);
-  ~AXUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp
index e1a7530c35..1c4709af16 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp
@@ -30,10 +30,6 @@ AXWiiUCode::AXWiiUCode(DSPHLE* dsphle, u32 crc) : AXUCode(dsphle, crc), m_last_m
   m_old_axwii = (crc == 0xfa450138) || (crc == 0x7699af32);
 }
 
-AXWiiUCode::~AXWiiUCode()
-{
-}
-
 void AXWiiUCode::HandleCommandList()
 {
   // Temp variables for addresses computation
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.h b/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.h
index 7d1baf871d..27d79ba1ae 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.h
@@ -15,7 +15,6 @@ class AXWiiUCode : public AXUCode
 {
 public:
   AXWiiUCode(DSPHLE* dsphle, u32 crc);
-  ~AXWiiUCode() override;
 
   void DoState(PointerWrap& p) override;
 
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
index bf8da5db10..4ad47757f8 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp
@@ -16,11 +16,6 @@ CARDUCode::CARDUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
   INFO_LOG_FMT(DSPHLE, "CARDUCode - initialized");
 }
 
-CARDUCode::~CARDUCode()
-{
-  m_mail_handler.Clear();
-}
-
 void CARDUCode::Initialize()
 {
   m_mail_handler.PushMail(DSP_INIT);
@@ -28,8 +23,8 @@ void CARDUCode::Initialize()
 
 void CARDUCode::Update()
 {
-  // check if we have to sent something
-  if (!m_mail_handler.IsEmpty())
+  // check if we have something to send
+  if (m_mail_handler.HasPending())
   {
     DSP::GenerateDSPInterruptFromDSPEmu(DSP::INT_DSP);
   }
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.h b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.h
index 99dcd2f231..55b1e7f95d 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/CARD.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/CARD.h
@@ -14,7 +14,6 @@ class CARDUCode : public UCodeInterface
 {
 public:
   CARDUCode(DSPHLE* dsphle, u32 crc);
-  ~CARDUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
index b734d16d4c..f6eae73088 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp
@@ -73,11 +73,6 @@ GBAUCode::GBAUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
 {
 }
 
-GBAUCode::~GBAUCode()
-{
-  m_mail_handler.Clear();
-}
-
 void GBAUCode::Initialize()
 {
   m_mail_handler.PushMail(DSP_INIT);
@@ -85,8 +80,8 @@ void GBAUCode::Initialize()
 
 void GBAUCode::Update()
 {
-  // check if we have to send something
-  if (!m_mail_handler.IsEmpty())
+  // check if we have something to send
+  if (m_mail_handler.HasPending())
   {
     DSP::GenerateDSPInterruptFromDSPEmu(DSP::INT_DSP);
   }
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.h b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.h
index 89c9ac4af8..22083d127d 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/GBA.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/GBA.h
@@ -18,7 +18,6 @@ void ProcessGBACrypto(u32 address);
 struct GBAUCode : public UCodeInterface
 {
   GBAUCode(DSPHLE* dsphle, u32 crc);
-  ~GBAUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/INIT.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/INIT.cpp
index 6df84313f1..7869460bc1 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/INIT.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/INIT.cpp
@@ -16,10 +16,6 @@ INITUCode::INITUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
   INFO_LOG_FMT(DSPHLE, "INITUCode - initialized");
 }
 
-INITUCode::~INITUCode()
-{
-}
-
 void INITUCode::Initialize()
 {
   m_mail_handler.PushMail(0x80544348);
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/INIT.h b/Source/Core/Core/HW/DSPHLE/UCodes/INIT.h
index 9b286065c2..53cbe01428 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/INIT.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/INIT.h
@@ -14,7 +14,6 @@ class INITUCode : public UCodeInterface
 {
 public:
   INITUCode(DSPHLE* dsphle, u32 crc);
-  ~INITUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
index e41a5b19c0..cd5e72a009 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp
@@ -28,13 +28,8 @@ ROMUCode::ROMUCode(DSPHLE* dsphle, u32 crc)
   INFO_LOG_FMT(DSPHLE, "UCode_Rom - initialized");
 }
 
-ROMUCode::~ROMUCode()
-{
-}
-
 void ROMUCode::Initialize()
 {
-  m_mail_handler.Clear();
   m_mail_handler.PushMail(0x8071FEED);
 }
 
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.h b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.h
index bf43d34f71..431c9ed052 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/ROM.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/ROM.h
@@ -14,7 +14,6 @@ class ROMUCode : public UCodeInterface
 {
 public:
   ROMUCode(DSPHLE* dsphle, u32 crc);
-  ~ROMUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp
index a3bf46fb9f..42e16cb687 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp
@@ -128,11 +128,6 @@ ZeldaUCode::ZeldaUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
   INFO_LOG_FMT(DSPHLE, "Zelda UCode loaded, crc={:08x}, flags={:08x}", crc, m_flags);
 }
 
-ZeldaUCode::~ZeldaUCode()
-{
-  m_mail_handler.Clear();
-}
-
 void ZeldaUCode::Initialize()
 {
   if (m_flags & LIGHT_PROTOCOL)
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.h b/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.h
index 941f140dea..6051faf853 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/Zelda.h
@@ -191,7 +191,6 @@ class ZeldaUCode : public UCodeInterface
 {
 public:
   ZeldaUCode(DSPHLE* dsphle, u32 crc);
-  ~ZeldaUCode() override;
 
   void Initialize() override;
   void HandleMail(u32 mail) override;