diff --git a/Source/Core/Common/I2C.cpp b/Source/Core/Common/I2C.cpp
index 4490912814..419c0e2f1f 100644
--- a/Source/Core/Common/I2C.cpp
+++ b/Source/Core/Common/I2C.cpp
@@ -51,7 +51,11 @@ int I2CBusSimple::BusRead(u8 slave_addr, u8 addr, int count, u8* data_out)
     {
       // TODO: Does this make sense? The transmitter can't NACK a read... it's the receiver that
       // does that
-      data_out[i] = slave->ReadByte(addr + i);
+      auto byte = slave->ReadByte(addr + i);
+      if (byte.has_value())
+        data_out[i] = byte.value();
+      else
+        return i;
     }
     return count;
   }
@@ -203,7 +207,18 @@ void I2CBus::SCLRisingEdge(const bool sda)
     ASSERT_MSG(WII_IPC, slave != nullptr,
                "Expected device with ID {:02x} to be on the I2C bus as it was earlier",
                i2c_address.value());
-    current_byte = slave->ReadByte(device_address.value());
+    std::optional<u8> byte = slave->ReadByte(device_address.value());
+    if (!byte.has_value())
+    {
+      WARN_LOG_FMT(WII_IPC, "Failed to read from device {:02x} at address {:02x}",
+                   i2c_address.value(), device_address.value());
+      // TODO
+      current_byte = 0xff;
+    }
+    else
+    {
+      current_byte = byte.value();
+    }
     // INFO_LOG_FMT(WII_IPC, "AVE: Read from {:02x} ({}) -> {:02x}", device_address.value(),
     //              IOS::GetAVERegisterName(device_address.value()), current_byte);
   }
diff --git a/Source/Core/Common/I2C.h b/Source/Core/Common/I2C.h
index a98f63fda6..16fcd8dc06 100644
--- a/Source/Core/Common/I2C.h
+++ b/Source/Core/Common/I2C.h
@@ -17,27 +17,30 @@ class I2CSlave
 {
 public:
   virtual bool Matches(u8 slave_addr) = 0;
-  virtual u8 ReadByte(u8 addr) = 0;
+  virtual std::optional<u8> ReadByte(u8 addr) = 0;
   virtual bool WriteByte(u8 addr, u8 value) = 0;
+};
 
-protected:
-  ~I2CSlave() = default;
-
-  template<typename T>
-  static u8 RawRead(T* reg_data, u8 addr)
+template <u8 slave_addr_val, typename T>
+class I2CSlaveSimple : I2CSlave
+{
+public:
+  bool Matches(u8 slave_addr) override { return slave_addr == slave_addr_val; }
+  std::optional<u8> ReadByte(u8 addr) { return data_bytes[addr]; }
+  bool WriteByte(u8 addr, u8 value)
   {
-    static_assert(std::is_standard_layout_v<T> && std::is_trivially_copyable_v<T>);
-    static_assert(sizeof(T) == 0x100);
-    return reinterpret_cast<u8*>(reg_data)[addr];
+    data_bytes[addr] = value;
+    return true;
   }
 
-  template <typename T>
-  static void RawWrite(T* reg_data, u8 addr, u8 value)
+  union
   {
-    static_assert(std::is_standard_layout_v<T> && std::is_trivially_copyable_v<T>);
-    static_assert(sizeof(T) == 0x100);
-    reinterpret_cast<u8*>(reg_data)[addr] = value;
-  }
+    T data;
+    std::array<u8, 0x100> data_bytes;
+  };
+
+  static_assert(std::is_standard_layout_v<T> && std::is_trivially_copyable_v<T>);
+  static_assert(sizeof(T) == 0x100);
 };
 
 class I2CBusBase
diff --git a/Source/Core/Core/HW/WiimoteEmu/Camera.cpp b/Source/Core/Core/HW/WiimoteEmu/Camera.cpp
index b253042e68..1dcdb77952 100644
--- a/Source/Core/Core/HW/WiimoteEmu/Camera.cpp
+++ b/Source/Core/Core/HW/WiimoteEmu/Camera.cpp
@@ -29,20 +29,26 @@ void CameraLogic::DoState(PointerWrap& p)
   // FYI: m_is_enabled is handled elsewhere.
 }
 
-bool CameraLogic::Matches(u8 slave_addr)
+int CameraLogic::BusRead(u8 slave_addr, u8 addr, int count, u8* data_out)
 {
-  return I2C_ADDR == slave_addr && m_is_enabled;
+  if (I2C_ADDR != slave_addr)
+    return 0;
+
+  if (!m_is_enabled)
+    return 0;
+
+  return RawRead(&m_reg_data, addr, count, data_out);
 }
 
-u8 CameraLogic::ReadByte(u8 addr)
+int CameraLogic::BusWrite(u8 slave_addr, u8 addr, int count, const u8* data_in)
 {
-  return RawRead(&m_reg_data, addr);
-}
+  if (I2C_ADDR != slave_addr)
+    return 0;
 
-bool CameraLogic::WriteByte(u8 addr, u8 value)
-{
-  RawWrite(&m_reg_data, addr, value);
-  return true;
+  if (!m_is_enabled)
+    return 0;
+
+  return RawWrite(&m_reg_data, addr, count, data_in);
 }
 
 std::array<CameraPoint, CameraLogic::NUM_POINTS>
diff --git a/Source/Core/Core/HW/WiimoteEmu/Camera.h b/Source/Core/Core/HW/WiimoteEmu/Camera.h
index c3b51598c7..23e21cc84e 100644
--- a/Source/Core/Core/HW/WiimoteEmu/Camera.h
+++ b/Source/Core/Core/HW/WiimoteEmu/Camera.h
@@ -5,8 +5,8 @@
 
 #include "Common/ChunkFile.h"
 #include "Common/CommonTypes.h"
-#include "Common/I2C.h"
 #include "Core/HW/WiimoteEmu/Dynamics.h"
+#include "Core/HW/WiimoteEmu/I2CBus.h"
 #include "InputCommon/ControllerEmu/ControlGroup/Cursor.h"
 
 namespace Common
@@ -101,7 +101,7 @@ struct IRFull : IRExtended
 };
 static_assert(sizeof(IRFull) == 9, "Wrong size");
 
-class CameraLogic : public Common::I2CSlave
+class CameraLogic : public I2CSlave
 {
 public:
   // OEM sensor bar distance between LED clusters in meters.
@@ -175,9 +175,9 @@ public:
   // The real wiimote reads camera data from the i2c bus at offset 0x37:
   static const u8 REPORT_DATA_OFFSET = offsetof(Register, camera_data);
 
-  bool Matches(u8 slave_addr) override;
-  u8 ReadByte(u8 addr) override;
-  bool WriteByte(u8 addr, u8 value) override;
+private:
+  int BusRead(u8 slave_addr, u8 addr, int count, u8* data_out) override;
+  int BusWrite(u8 slave_addr, u8 addr, int count, const u8* data_in) override;
 
   Register m_reg_data{};
 
diff --git a/Source/Core/Core/HW/WiimoteEmu/Extension/Extension.cpp b/Source/Core/Core/HW/WiimoteEmu/Extension/Extension.cpp
index ebc034ed74..fd2b185872 100644
--- a/Source/Core/Core/HW/WiimoteEmu/Extension/Extension.cpp
+++ b/Source/Core/Core/HW/WiimoteEmu/Extension/Extension.cpp
@@ -71,19 +71,14 @@ void None::DoState(PointerWrap& p)
   // Nothing needed.
 }
 
-bool None::Matches(u8 slave_addr)
+int None::BusRead(u8 slave_addr, u8 addr, int count, u8* data_out)
 {
-  return false;
+  return 0;
 }
 
-std::optional<u8> None::ReadByte(u8 addr)
+int None::BusWrite(u8 slave_addr, u8 addr, int count, const u8* data_in)
 {
-  return std::nullopt;
-}
-
-bool None::WriteByte(u8 addr, u8 value)
-{
-  return false;
+  return 0;
 }
 
 bool EncryptedExtension::ReadDeviceDetectPin() const
diff --git a/Source/Core/Core/HW/WiimoteEmu/Extension/Extension.h b/Source/Core/Core/HW/WiimoteEmu/Extension/Extension.h
index e2fe729d50..4a055c597d 100644
--- a/Source/Core/Core/HW/WiimoteEmu/Extension/Extension.h
+++ b/Source/Core/Core/HW/WiimoteEmu/Extension/Extension.h
@@ -10,15 +10,15 @@
 
 #include "Common/ChunkFile.h"
 #include "Common/CommonTypes.h"
-#include "Common/I2C.h"
 #include "Core/HW/WiimoteEmu/Encryption.h"
+#include "Core/HW/WiimoteEmu/I2CBus.h"
 #include "InputCommon/ControllerEmu/ControllerEmu.h"
 
 namespace WiimoteEmu
 {
 struct DesiredExtensionState;
 
-class Extension : public ControllerEmu::EmulatedController, public Common::I2CSlave
+class Extension : public ControllerEmu::EmulatedController, public I2CSlave
 {
 public:
   explicit Extension(const char* name);
@@ -56,9 +56,8 @@ private:
   void Reset() override;
   void DoState(PointerWrap& p) override;
 
-  bool Matches(u8 slave_addr) override;
-  std::optional<u8> ReadByte(u8 addr) override;
-  bool WriteByte(u8 addr, u8 value) override;
+  int BusRead(u8 slave_addr, u8 addr, int count, u8* data_out) override;
+  int BusWrite(u8 slave_addr, u8 addr, int count, const u8* data_in) override;
 };
 
 // This class provides the encryption and initialization behavior of most extensions.
diff --git a/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.cpp b/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.cpp
index c5043298b8..97e73ea4bc 100644
--- a/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.cpp
+++ b/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.cpp
@@ -3,9 +3,11 @@
 
 #include "Core/HW/WiimoteEmu/ExtensionPort.h"
 
+#include "Common/ChunkFile.h"
+
 namespace WiimoteEmu
 {
-ExtensionPort::ExtensionPort(Common::I2CBusBase* i2c_bus) : m_i2c_bus(*i2c_bus)
+ExtensionPort::ExtensionPort(I2CBus* i2c_bus) : m_i2c_bus(*i2c_bus)
 {
 }
 
diff --git a/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.h b/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.h
index 3c6c70e62a..86b1fd31f9 100644
--- a/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.h
+++ b/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.h
@@ -3,8 +3,9 @@
 
 #pragma once
 
-#include "Common/I2C.h"
+#include "Common/ChunkFile.h"
 #include "Core/HW/WiimoteEmu/Extension/Extension.h"
+#include "Core/HW/WiimoteEmu/I2CBus.h"
 
 namespace WiimoteEmu
 {
@@ -34,14 +35,14 @@ public:
   static constexpr u8 REPORT_I2C_SLAVE = 0x52;
   static constexpr u8 REPORT_I2C_ADDR = 0x00;
 
-  explicit ExtensionPort(Common::I2CBusBase* i2c_bus);
+  explicit ExtensionPort(I2CBus* i2c_bus);
 
   bool IsDeviceConnected() const;
   void AttachExtension(Extension* dev);
 
 private:
   Extension* m_extension = nullptr;
-  Common::I2CBusBase& m_i2c_bus;
+  I2CBus& m_i2c_bus;
 };
 
 }  // namespace WiimoteEmu
diff --git a/Source/Core/Core/HW/WiimoteEmu/I2CBus.cpp b/Source/Core/Core/HW/WiimoteEmu/I2CBus.cpp
index e69de29bb2..19202350fd 100644
--- a/Source/Core/Core/HW/WiimoteEmu/I2CBus.cpp
+++ b/Source/Core/Core/HW/WiimoteEmu/I2CBus.cpp
@@ -0,0 +1,53 @@
+// Copyright 2019 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "Core/HW/WiimoteEmu/I2CBus.h"
+
+#include <algorithm>
+
+namespace WiimoteEmu
+{
+void I2CBus::AddSlave(I2CSlave* slave)
+{
+  m_slaves.emplace_back(slave);
+}
+
+void I2CBus::RemoveSlave(I2CSlave* slave)
+{
+  m_slaves.erase(std::remove(m_slaves.begin(), m_slaves.end(), slave), m_slaves.end());
+}
+
+void I2CBus::Reset()
+{
+  m_slaves.clear();
+}
+
+int I2CBus::BusRead(u8 slave_addr, u8 addr, int count, u8* data_out)
+{
+  for (auto& slave : m_slaves)
+  {
+    auto const bytes_read = slave->BusRead(slave_addr, addr, count, data_out);
+
+    // A slave responded, we are done.
+    if (bytes_read)
+      return bytes_read;
+  }
+
+  return 0;
+}
+
+int I2CBus::BusWrite(u8 slave_addr, u8 addr, int count, const u8* data_in)
+{
+  for (auto& slave : m_slaves)
+  {
+    auto const bytes_written = slave->BusWrite(slave_addr, addr, count, data_in);
+
+    // A slave responded, we are done.
+    if (bytes_written)
+      return bytes_written;
+  }
+
+  return 0;
+}
+
+}  // namespace WiimoteEmu
diff --git a/Source/Core/Core/HW/WiimoteEmu/I2CBus.h b/Source/Core/Core/HW/WiimoteEmu/I2CBus.h
index e69de29bb2..3a1e0a67d3 100644
--- a/Source/Core/Core/HW/WiimoteEmu/I2CBus.h
+++ b/Source/Core/Core/HW/WiimoteEmu/I2CBus.h
@@ -0,0 +1,75 @@
+// Copyright 2019 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <algorithm>
+#include <vector>
+
+#include "Common/CommonTypes.h"
+
+namespace WiimoteEmu
+{
+class I2CBus;
+
+class I2CSlave
+{
+  friend I2CBus;
+
+protected:
+  virtual ~I2CSlave() = default;
+
+  virtual int BusRead(u8 slave_addr, u8 addr, int count, u8* data_out) = 0;
+  virtual int BusWrite(u8 slave_addr, u8 addr, int count, const u8* data_in) = 0;
+
+  template <typename T>
+  static int RawRead(T* reg_data, u8 addr, int count, u8* data_out)
+  {
+    static_assert(std::is_standard_layout_v<T> && std::is_trivially_copyable_v<T>);
+    static_assert(0x100 == sizeof(T));
+
+    // TODO: addr wraps around after 0xff
+
+    u8* src = reinterpret_cast<u8*>(reg_data) + addr;
+    count = std::min(count, int(reinterpret_cast<u8*>(reg_data + 1) - src));
+
+    std::copy_n(src, count, data_out);
+
+    return count;
+  }
+
+  template <typename T>
+  static int RawWrite(T* reg_data, u8 addr, int count, const u8* data_in)
+  {
+    static_assert(std::is_standard_layout_v<T> && std::is_trivially_copyable_v<T>);
+    static_assert(0x100 == sizeof(T));
+
+    // TODO: addr wraps around after 0xff
+
+    u8* dst = reinterpret_cast<u8*>(reg_data) + addr;
+    count = std::min(count, int(reinterpret_cast<u8*>(reg_data + 1) - dst));
+
+    std::copy_n(data_in, count, dst);
+
+    return count;
+  }
+};
+
+class I2CBus
+{
+public:
+  void AddSlave(I2CSlave* slave);
+  void RemoveSlave(I2CSlave* slave);
+
+  void Reset();
+
+  // TODO: change int to u16 or something
+  int BusRead(u8 slave_addr, u8 addr, int count, u8* data_out);
+  int BusWrite(u8 slave_addr, u8 addr, int count, const u8* data_in);
+
+private:
+  // Pointers are unowned:
+  std::vector<I2CSlave*> m_slaves;
+};
+
+}  // namespace WiimoteEmu
diff --git a/Source/Core/Core/HW/WiimoteEmu/MotionPlus.h b/Source/Core/Core/HW/WiimoteEmu/MotionPlus.h
index ccbc0605c3..02ddfb7ec2 100644
--- a/Source/Core/Core/HW/WiimoteEmu/MotionPlus.h
+++ b/Source/Core/Core/HW/WiimoteEmu/MotionPlus.h
@@ -248,9 +248,8 @@ private:
   ActivationStatus GetActivationStatus() const;
   PassthroughMode GetPassthroughMode() const;
 
-  bool Matches(u8 slave_addr) override;
-  u8 ReadByte(u8 addr) override;
-  bool WriteByte(u8 addr, u8 value) override;
+  int BusRead(u8 slave_addr, u8 addr, int count, u8* data_out) override;
+  int BusWrite(u8 slave_addr, u8 addr, int count, const u8* data_in) override;
 
   bool ReadDeviceDetectPin() const override;
 
@@ -260,7 +259,7 @@ private:
   u8 m_progress_timer = {};
 
   // The port on the end of the motion plus:
-  Common::I2CBusSimple m_i2c_bus;
+  I2CBus m_i2c_bus;
   ExtensionPort m_extension_port{&m_i2c_bus};
 };
 }  // namespace WiimoteEmu
diff --git a/Source/Core/Core/HW/WiimoteEmu/Speaker.cpp b/Source/Core/Core/HW/WiimoteEmu/Speaker.cpp
index 99b9b82912..23cba6bfd7 100644
--- a/Source/Core/Core/HW/WiimoteEmu/Speaker.cpp
+++ b/Source/Core/Core/HW/WiimoteEmu/Speaker.cpp
@@ -153,29 +153,30 @@ void SpeakerLogic::SetSpeakerEnabled(bool enabled)
   m_speaker_enabled = enabled;
 }
 
-bool SpeakerLogic::Matches(u8 slave_addr)
+int SpeakerLogic::BusRead(u8 slave_addr, u8 addr, int count, u8* data_out)
 {
-  return I2C_ADDR == slave_addr;
+  if (I2C_ADDR != slave_addr)
+    return 0;
+
+  return RawRead(&reg_data, addr, count, data_out);
 }
 
-u8 SpeakerLogic::ReadByte(u8 addr)
+int SpeakerLogic::BusWrite(u8 slave_addr, u8 addr, int count, const u8* data_in)
 {
-  return RawRead(&reg_data, addr);
-}
+  if (I2C_ADDR != slave_addr)
+    return 0;
 
-bool SpeakerLogic::WriteByte(u8 addr, u8 value)
-{
   if (0x00 == addr)
   {
     SpeakerData(data_in, count, m_speaker_pan_setting.GetValue() / 100);
-    // TODO: Does writing immediately change the decoder config even when active
-    // or does a write to 0x08 activate the new configuration or something?
+    return count;
   }
   else
   {
-    RawWrite(&reg_data, addr, value);
+    // TODO: Does writing immediately change the decoder config even when active
+    // or does a write to 0x08 activate the new configuration or something?
+    return RawWrite(&reg_data, addr, count, data_in);
   }
-  return true;
 }
 
 }  // namespace WiimoteEmu
diff --git a/Source/Core/Core/HW/WiimoteEmu/Speaker.h b/Source/Core/Core/HW/WiimoteEmu/Speaker.h
index 995ccd2f0c..9a6a652bb1 100644
--- a/Source/Core/Core/HW/WiimoteEmu/Speaker.h
+++ b/Source/Core/Core/HW/WiimoteEmu/Speaker.h
@@ -5,7 +5,7 @@
 
 #include "Common/ChunkFile.h"
 #include "Common/CommonTypes.h"
-#include "Common/I2C.h"
+#include "Core/HW/WiimoteEmu/I2CBus.h"
 #include "InputCommon/ControllerEmu/Setting/NumericSetting.h"
 
 namespace WiimoteEmu
@@ -17,7 +17,7 @@ struct ADPCMState
 
 class Wiimote;
 
-class SpeakerLogic : public Common::I2CSlave
+class SpeakerLogic : public I2CSlave
 {
   friend class Wiimote;
 
@@ -63,9 +63,8 @@ private:
 
   static_assert(0x100 == sizeof(Register));
 
-  bool Matches(u8 slave_addr) override;
-  u8 ReadByte(u8 addr) override;
-  bool WriteByte(u8 addr, u8 value) override;
+  int BusRead(u8 slave_addr, u8 addr, int count, u8* data_out) override;
+  int BusWrite(u8 slave_addr, u8 addr, int count, const u8* data_in) override;
 
   Register reg_data{};
 
diff --git a/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.h b/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.h
index 8468e4dc60..e364ccdb6c 100644
--- a/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.h
+++ b/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.h
@@ -10,7 +10,6 @@
 
 #include "Common/Common.h"
 #include "Common/Config/Config.h"
-#include "Common/I2C.h"
 
 #include "Core/HW/WiimoteCommon/WiimoteReport.h"
 
@@ -18,6 +17,7 @@
 #include "Core/HW/WiimoteEmu/Dynamics.h"
 #include "Core/HW/WiimoteEmu/Encryption.h"
 #include "Core/HW/WiimoteEmu/ExtensionPort.h"
+#include "Core/HW/WiimoteEmu/I2CBus.h"
 #include "Core/HW/WiimoteEmu/MotionPlus.h"
 #include "Core/HW/WiimoteEmu/Speaker.h"
 
@@ -316,7 +316,7 @@ private:
   MotionPlus m_motion_plus;
   CameraLogic m_camera_logic;
 
-  Common::I2CBusSimple m_i2c_bus;
+  I2CBus m_i2c_bus;
 
   ExtensionPort m_extension_port{&m_i2c_bus};