diff --git a/src/cartridge.cpp b/src/cartridge.cpp
index 9494b8d..7834fb4 100644
--- a/src/cartridge.cpp
+++ b/src/cartridge.cpp
@@ -44,9 +44,9 @@ bool Cartridge::loadRom(std::string path)
     romSize = ftell(romFile);
     fseek(romFile, 0, SEEK_SET);
 
-    // Choose the save extension based on the instance number
+    // Choose the save extension based on the instance ID
     // This ensures multiple instances don't write over the same file
-    std::string ext = number ? (".sv" + std::to_string(number + 1)) : ".sav";
+    std::string ext = core->getId() ? (".sv" + std::to_string(core->getId() + 1)) : ".sav";
 
     // Attempt to load the ROM's save into memory
     saveName = path.substr(0, path.rfind(".")) + ext;
diff --git a/src/cartridge.h b/src/cartridge.h
index eaff965..cbe03fc 100644
--- a/src/cartridge.h
+++ b/src/cartridge.h
@@ -38,7 +38,7 @@ enum NdsCmdMode
 class Cartridge
 {
     public:
-        Cartridge(Core *core, int number): core(core), number(number) {}
+        Cartridge(Core *core): core(core) {}
         ~Cartridge();
 
         virtual bool loadRom(std::string path);
@@ -52,7 +52,6 @@ class Cartridge
 
     protected:
         Core *core;
-        int number;
 
         FILE *romFile = nullptr;
         uint8_t *rom = nullptr, *save = nullptr;
@@ -69,7 +68,7 @@ class Cartridge
 class CartridgeNds: public Cartridge
 {
     public:
-        CartridgeNds(Core *core, int number): Cartridge(core, number) {}
+        CartridgeNds(Core *core): Cartridge(core) {}
 
         bool loadRom(std::string path);
         void directBoot();
@@ -115,7 +114,7 @@ class CartridgeNds: public Cartridge
 class CartridgeGba: public Cartridge
 {
     public:
-        CartridgeGba(Core *core, int number): Cartridge(core, number) {}
+        CartridgeGba(Core *core): Cartridge(core) {}
 
         bool loadRom(std::string path);
 
diff --git a/src/core.cpp b/src/core.cpp
index 36d5c54..d21b756 100644
--- a/src/core.cpp
+++ b/src/core.cpp
@@ -24,9 +24,10 @@
 #include "core.h"
 #include "settings.h"
 
-Core::Core(std::string ndsPath, std::string gbaPath, int number):
-    cartridgeNds(this, number),
-    cartridgeGba(this, number),
+Core::Core(std::string ndsPath, std::string gbaPath, int id):
+    id(id),
+    cartridgeNds(this),
+    cartridgeGba(this),
     cp15(this),
     divSqrt(this),
     dldi(this),
@@ -40,7 +41,7 @@ Core::Core(std::string ndsPath, std::string gbaPath, int number):
     ipc(this),
     memory(this),
     rtc(this),
-    spi(this, number),
+    spi(this),
     spu(this),
     timers { Timers(this, 0), Timers(this, 1) },
     wifi(this)
diff --git a/src/core.h b/src/core.h
index 0f195b3..c4c2405 100644
--- a/src/core.h
+++ b/src/core.h
@@ -66,11 +66,12 @@ struct Task
 class Core
 {
     public:
-        Core(std::string ndsPath = "", std::string gbaPath = "", int number = 0);
+        Core(std::string ndsPath = "", std::string gbaPath = "", int id = 0);
 
         void runFrame() { (this->*runFunc)(); }
 
         bool isGbaMode() { return gbaMode; }
+        int  getId()     { return id;      }
         int  getFps()    { return fps;     }
 
         uint32_t getGlobalCycles() { return globalCycles; }
@@ -100,8 +101,9 @@ class Core
         Wifi wifi;
 
     private:
-        bool gbaMode = false;
         void (Core::*runFunc)() = &Core::runNdsFrame;
+        bool gbaMode = false;
+        int id = 0;
 
         std::vector<Task> tasks;
         uint32_t globalCycles = 0;
diff --git a/src/desktop/layout_dialog.cpp b/src/desktop/layout_dialog.cpp
index 1c771a8..5faf4d8 100644
--- a/src/desktop/layout_dialog.cpp
+++ b/src/desktop/layout_dialog.cpp
@@ -63,7 +63,7 @@ EVT_BUTTON(wxID_CANCEL,       LayoutDialog::cancel)
 EVT_BUTTON(wxID_OK,           LayoutDialog::confirm)
 wxEND_EVENT_TABLE()
 
-LayoutDialog::LayoutDialog(NooFrame *frame): wxDialog(nullptr, wxID_ANY, "Screen Layout"), frame(frame)
+LayoutDialog::LayoutDialog(NooApp *app): wxDialog(nullptr, wxID_ANY, "Screen Layout"), app(app)
 {
     // Remember the previous settings in case the changes are discarded
     prevSettings[0] = ScreenLayout::getScreenRotation();
@@ -173,144 +173,112 @@ void LayoutDialog::rotateNone(wxCommandEvent &event)
 {
     // Set the screen rotation setting to none
     ScreenLayout::setScreenRotation(0);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::rotateCw(wxCommandEvent &event)
 {
     // Set the screen rotation setting to clockwise
     ScreenLayout::setScreenRotation(1);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::rotateCcw(wxCommandEvent &event)
 {
     // Set the screen rotation setting to counter-clockwise
     ScreenLayout::setScreenRotation(2);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::arrangeAuto(wxCommandEvent &event)
 {
     // Set the screen arrangement setting to automatic
     ScreenLayout::setScreenArrangement(0);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::arrangeVert(wxCommandEvent &event)
 {
     // Set the screen arrangement setting to vertical
     ScreenLayout::setScreenArrangement(1);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::arrangeHori(wxCommandEvent &event)
 {
     // Set the screen arrangement setting to horizontal
     ScreenLayout::setScreenArrangement(2);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::sizeEven(wxCommandEvent &event)
 {
     // Set the screen sizing setting to even
     ScreenLayout::setScreenSizing(0);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::sizeTop(wxCommandEvent &event)
 {
     // Set the screen sizing setting to enlarge top
     ScreenLayout::setScreenSizing(1);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::sizeBot(wxCommandEvent &event)
 {
     // Set the screen sizing setting to enlarge bottom
     ScreenLayout::setScreenSizing(2);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::gapNone(wxCommandEvent &event)
 {
     // Set the screen gap setting to none
     ScreenLayout::setScreenGap(0);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::gapQuart(wxCommandEvent &event)
 {
     // Set the screen gap setting to quarter
     ScreenLayout::setScreenGap(1);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::gapHalf(wxCommandEvent &event)
 {
     // Set the screen gap setting to half
     ScreenLayout::setScreenGap(2);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::gapFull(wxCommandEvent &event)
 {
     // Set the screen gap setting to full
     ScreenLayout::setScreenGap(3);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::intScale(wxCommandEvent &event)
 {
     // Toggle the integer scale setting
     ScreenLayout::setIntegerScale(!ScreenLayout::getIntegerScale());
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::gbaCrop(wxCommandEvent &event)
 {
     // Toggle the GBA crop setting
     ScreenLayout::setGbaCrop(!ScreenLayout::getGbaCrop());
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::filter(wxCommandEvent &event)
 {
     // Toggle the screen filter setting
     NooApp::setScreenFilter(!NooApp::getScreenFilter());
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 }
 
 void LayoutDialog::cancel(wxCommandEvent &event)
@@ -323,9 +291,7 @@ void LayoutDialog::cancel(wxCommandEvent &event)
     ScreenLayout::setIntegerScale(prevSettings[4]);
     ScreenLayout::setGbaCrop(prevSettings[5]);
     NooApp::setScreenFilter(prevSettings[6]);
-
-    // Trigger a resize to update the screen layout
-    frame->SendSizeEvent();
+    app->updateLayouts();
 
     event.Skip(true);
 }
diff --git a/src/desktop/layout_dialog.h b/src/desktop/layout_dialog.h
index 1ce9b56..c5c7c1c 100644
--- a/src/desktop/layout_dialog.h
+++ b/src/desktop/layout_dialog.h
@@ -22,15 +22,15 @@
 
 #include <wx/wx.h>
 
-#include "noo_frame.h"
+class NooApp;
 
 class LayoutDialog: public wxDialog
 {
     public:
-        LayoutDialog(NooFrame *frame);
+        LayoutDialog(NooApp *app);
 
     private:
-        NooFrame *frame;
+        NooApp *app;
 
         int prevSettings[7];
 
diff --git a/src/desktop/noo_app.cpp b/src/desktop/noo_app.cpp
index 12b35cd..0b4c52f 100644
--- a/src/desktop/noo_app.cpp
+++ b/src/desktop/noo_app.cpp
@@ -106,7 +106,7 @@ bool NooApp::OnInit()
 
 void NooApp::createFrame()
 {
-    // Create a new frame using the lowest free instance number
+    // Create a new frame using the lowest free instance ID
     for (int i = 0; i < MAX_FRAMES; i++)
     {
         if (!frames[i])
@@ -117,31 +117,41 @@ void NooApp::createFrame()
     }
 }
 
-void NooApp::removeFrame(int number)
+void NooApp::removeFrame(int id)
 {
-    // Free an instance number; this should be done on frame destruction
-    frames[number] = nullptr;
+    // Free an instance ID; this should be done on frame destruction
+    frames[id] = nullptr;
 }
 
-void NooApp::connectCore(int number)
+void NooApp::connectCore(int id)
 {
     // Connect a frame's core to all other active cores
     for (int i = 0; i < MAX_FRAMES; i++)
     {
-        if (!frames[i] || i == number) continue;
+        if (!frames[i] || i == id) continue;
         if (Core *core = frames[i]->getCore())
-            core->wifi.addConnection(frames[number]->getCore());
+            core->wifi.addConnection(frames[id]->getCore());
     }
 }
 
-void NooApp::disconnCore(int number)
+void NooApp::disconnCore(int id)
 {
     // Disconnect a frame's core from all other active cores
     for (int i = 0; i < MAX_FRAMES; i++)
     {
-        if (!frames[i] || i == number) continue;
+        if (!frames[i] || i == id) continue;
         if (Core *core = frames[i]->getCore())
-            core->wifi.remConnection(frames[number]->getCore());
+            core->wifi.remConnection(frames[id]->getCore());
+    }
+}
+
+void NooApp::updateLayouts()
+{
+    // Trigger resize events for frames to update screen layouts
+    for (size_t i = 0; i < MAX_FRAMES; i++)
+    {
+        if (frames[i])
+            frames[i]->SendSizeEvent();
     }
 }
 
@@ -163,7 +173,7 @@ int NooApp::audioCallback(const void *in, void *out, unsigned long count,
     uint32_t *original = nullptr;
 
     // Get samples from each instance so frame limiting is enforced
-    // Only the lowest instance number's samples are played; the rest are discarded
+    // Only the lowest instance ID's samples are played; the rest are discarded
     for (size_t i = 0; i < MAX_FRAMES; i++)
     {
         if (!frames[i]) continue;
diff --git a/src/desktop/noo_app.h b/src/desktop/noo_app.h
index 0f85402..5a274d6 100644
--- a/src/desktop/noo_app.h
+++ b/src/desktop/noo_app.h
@@ -31,10 +31,12 @@ class NooApp: public wxApp
 {
     public:
         void createFrame();
-        void removeFrame(int number);
+        void removeFrame(int id);
 
-        void connectCore(int number);
-        void disconnCore(int number);
+        void connectCore(int id);
+        void disconnCore(int id);
+
+        void updateLayouts();
 
         static int getScreenFilter()     { return screenFilter;    }
         static int getKeyBind(int index) { return keyBinds[index]; }
diff --git a/src/desktop/noo_frame.cpp b/src/desktop/noo_frame.cpp
index 263e53d..a1ca4b9 100644
--- a/src/desktop/noo_frame.cpp
+++ b/src/desktop/noo_frame.cpp
@@ -81,8 +81,8 @@ EVT_DROP_FILES(NooFrame::dropFiles)
 EVT_CLOSE(NooFrame::close)
 wxEND_EVENT_TABLE()
 
-NooFrame::NooFrame(NooApp *app, int number, std::string path):
-    wxFrame(nullptr, wxID_ANY, "NooDS"), app(app), number(number)
+NooFrame::NooFrame(NooApp *app, int id, std::string path):
+    wxFrame(nullptr, wxID_ANY, "NooDS"), app(app), id(id)
 {
     // Set the icon
     wxIcon icon(icon_xpm);
@@ -163,7 +163,7 @@ NooFrame::NooFrame(NooApp *app, int number, std::string path):
     wxMenuBar *menuBar = new wxMenuBar();
     menuBar->Append(fileMenu,   "&File");
     menuBar->Append(systemMenu, "&System");
-    if (number == 0) // Only show settings in the main instance
+    if (id == 0) // Only show settings in the main instance
         menuBar->Append(settingsMenu, "&Settings");
     SetMenuBar(menuBar);
 
@@ -216,7 +216,7 @@ void NooFrame::Refresh()
 
     // Override the refresh function to also update the FPS counter
     wxString label = "NooDS";
-    if (number)  label += wxString::Format(" (%d)", number + 1);
+    if (id > 0)  label += wxString::Format(" (%d)", id + 1);
     if (running) label += wxString::Format(" - %d FPS", core->getFps());
     SetLabel(label);
 }
@@ -250,8 +250,8 @@ void NooFrame::startCore(bool full)
         try
         {
             // Attempt to boot the core
-            core = new Core(ndsPath, gbaPath, number);
-            app->connectCore(number);
+            core = new Core(ndsPath, gbaPath, id);
+            app->connectCore(id);
         }
         catch (CoreError e)
         {
@@ -336,7 +336,7 @@ void NooFrame::stopCore(bool full)
         // Shut down the core
         if (core)
         {
-            app->disconnCore(number);
+            app->disconnCore(id);
             delete core;
             core = nullptr;
         }
@@ -537,7 +537,7 @@ void NooFrame::inputSettings(wxCommandEvent &event)
 void NooFrame::layoutSettings(wxCommandEvent &event)
 {
     // Show the layout settings dialog
-    LayoutDialog layoutDialog(this);
+    LayoutDialog layoutDialog(app);
     layoutDialog.ShowModal();
 }
 
@@ -646,6 +646,6 @@ void NooFrame::close(wxCloseEvent &event)
 {
     // Properly shut down the emulator
     stopCore(true);
-    app->removeFrame(number);
+    app->removeFrame(id);
     event.Skip(true);
 }
diff --git a/src/desktop/noo_frame.h b/src/desktop/noo_frame.h
index e749426..7ff891b 100644
--- a/src/desktop/noo_frame.h
+++ b/src/desktop/noo_frame.h
@@ -31,7 +31,7 @@ class NooCanvas;
 class NooFrame: public wxFrame
 {
     public:
-        NooFrame(NooApp *app, int number = 0, std::string path = "");
+        NooFrame(NooApp *app, int id = 0, std::string path = "");
 
         void Refresh();
 
@@ -51,7 +51,7 @@ class NooFrame: public wxFrame
         wxJoystick *joystick;
         wxTimer *timer;
 
-        int number = 0;
+        int id = 0;
         Core *core = nullptr;
         bool running = false;
 
diff --git a/src/spi.cpp b/src/spi.cpp
index 0a0c318..e9b9eaf 100644
--- a/src/spi.cpp
+++ b/src/spi.cpp
@@ -61,11 +61,11 @@ bool Spi::loadFirmware()
         fread(firmware, sizeof(uint8_t), firmSize, file);
         fclose(file);
 
-        if (number > 0)
+        if (core->getId() > 0)
         {
-            // Increment the MAC address based on the instance number
+            // Increment the MAC address based on the instance ID
             // This allows instances to be detected as separate systems
-            firmware[0x36] += number;
+            firmware[0x36] += core->getId();
 
             // Recalculate the WiFi config CRC
             uint16_t crc = crc16(0, &firmware[0x2C], 0x138);
@@ -86,16 +86,16 @@ bool Spi::loadFirmware()
     firmware[0x21] = 0x3F; // User settings offset / 8, byte 2
 
     // Set some WiFi config data
-    firmware[0x2C] = 0x38;   // Config length, byte 1
-    firmware[0x2D] = 0x01;   // Config length, byte 2
-    firmware[0x36] = number; // MAC address, byte 1
-    firmware[0x37] = 0x09;   // MAC address, byte 2
-    firmware[0x38] = 0xBF;   // MAC address, byte 3
-    firmware[0x39] = 0x12;   // MAC address, byte 4
-    firmware[0x3A] = 0x34;   // MAC address, byte 5
-    firmware[0x3B] = 0x56;   // MAC address, byte 6
-    firmware[0x3C] = 0xFE;   // Enabled channels, byte 1
-    firmware[0x3D] = 0x3F;   // Enabled channels, byte 2
+    firmware[0x2C] = 0x38; // Config length, byte 1
+    firmware[0x2D] = 0x01; // Config length, byte 2
+    firmware[0x36] = core->getId(); // MAC address, byte 1
+    firmware[0x37] = 0x09; // MAC address, byte 2
+    firmware[0x38] = 0xBF; // MAC address, byte 3
+    firmware[0x39] = 0x12; // MAC address, byte 4
+    firmware[0x3A] = 0x34; // MAC address, byte 5
+    firmware[0x3B] = 0x56; // MAC address, byte 6
+    firmware[0x3C] = 0xFE; // Enabled channels, byte 1
+    firmware[0x3D] = 0x3F; // Enabled channels, byte 2
 
     // Calculate the WiFi config CRC
     uint16_t crc = crc16(0, &firmware[0x2C], 0x138);
diff --git a/src/spi.h b/src/spi.h
index 54132bb..eb2524f 100644
--- a/src/spi.h
+++ b/src/spi.h
@@ -27,7 +27,7 @@ class Core;
 class Spi
 {
     public:
-        Spi(Core *core, int number): core(core), number(number) {}
+        Spi(Core *core): core(core) {}
         ~Spi();
 
         bool loadFirmware();
@@ -44,7 +44,6 @@ class Spi
 
     private:
         Core *core;
-        int number;
 
         uint8_t *firmware = nullptr;
         size_t firmSize = 0;
diff --git a/src/wifi.cpp b/src/wifi.cpp
index b94ed94..83d0336 100644
--- a/src/wifi.cpp
+++ b/src/wifi.cpp
@@ -143,7 +143,7 @@ void Wifi::processPackets()
             {
                 wRxbufWrcsr++;
                 wRxbufWrcsr = (wRxbufBegin & 0x1FFE) + (wRxbufWrcsr - (wRxbufBegin & 0x1FFE)) % ((wRxbufEnd & 0x1FFE) - (wRxbufBegin & 0x1FFE));
-                wRxbufWrcsr &= 0x1FFF;
+                wRxbufWrcsr &= 0xFFF;
             }
         }
 
@@ -344,7 +344,7 @@ void Wifi::writeWTxbufWrData(uint16_t mask, uint16_t value)
     wTxbufWrAddr += 2;
     if (wTxbufWrAddr == wTxbufGap)
         wTxbufWrAddr += wTxbufGapdisp << 1;
-    wTxbufWrAddr %= 0x2000;
+    wTxbufWrAddr &= 0x1FFF;
 
     // Decrement the write counter and trigger an interrupt at the end
     if (wTxbufCount > 0 && --wTxbufCount == 0)
@@ -503,12 +503,14 @@ uint16_t Wifi::readWRxbufRdData()
     uint16_t value = core->memory.read<uint16_t>(1, 0x4804000 + wRxbufRdAddr);
 
     // Increment the read address
-    wRxbufRdAddr += 2;
-    if (wRxbufRdAddr == wRxbufGap)
-        wRxbufRdAddr += wRxbufGapdisp << 1;
     if ((wRxbufBegin & 0x1FFE) != (wRxbufEnd & 0x1FFE))
+    {
+        wRxbufRdAddr += 2;
+        if (wRxbufRdAddr == wRxbufGap)
+            wRxbufRdAddr += wRxbufGapdisp << 1;
         wRxbufRdAddr = (wRxbufBegin & 0x1FFE) + (wRxbufRdAddr - (wRxbufBegin & 0x1FFE)) % ((wRxbufEnd & 0x1FFE) - (wRxbufBegin & 0x1FFE));
-    wRxbufRdAddr %= 0x2000;
+        wRxbufRdAddr &= 0x1FFF;
+    }
 
     // Decrement the read counter and trigger an interrupt at the end
     if (wRxbufCount > 0 && --wRxbufCount == 0)