diff --git a/src/device/expansion2.cpp b/src/device/expansion2.cpp
index 66be4c8..b38e4d3 100644
--- a/src/device/expansion2.cpp
+++ b/src/device/expansion2.cpp
@@ -1,4 +1,5 @@
 #include "expansion2.h"
+#include "config.h"
 #include <cstdio>
 
 Expansion2::Expansion2() { reset(); }
@@ -6,16 +7,26 @@ Expansion2::Expansion2() { reset(); }
 void Expansion2::reset() { post = 0; }
 
 uint8_t Expansion2::read(uint32_t address) {
-    (void)address;
+    if (address == 0x21) {  // DUART Status
+        return 1 << 2;      // Tx Empty
+    }
     return 0;
 }
 
 void Expansion2::write(uint32_t address, uint8_t data) {
-    if (address == 0x41) {
+    if (address == 0x22) {  // DUART Command
+        // Ignore (Enable Tx/Rx, reset/flush commands)
+    } else if (address == 0x23) {  // DUART Tx
+        if (config.debug.log.system) {
+            putchar(data);
+        }
+    } else if (address == 0x24) {  // DUART Aux Control
+        // Ignore (baud rate, int flags)
+    } else if (address == 0x41) {
         post = data;
-    }
-    // PCSX-Redux/Openbios stdout channel
-    if (address == 0x80) {
-        putchar(data);
+    } else if (address == 0x80) {  // PCSX-Redux/Openbios stdout channel
+        if (config.debug.log.system) {
+            putchar(data);
+        }
     }
 }
\ No newline at end of file
diff --git a/src/system.cpp b/src/system.cpp
index 93d777a..5c71842 100644
--- a/src/system.cpp
+++ b/src/system.cpp
@@ -498,6 +498,20 @@ bool System::loadBios(const std::string& path) {
     this->biosPath = path;
     state = State::run;
     biosLoaded = true;
+
+    auto patch = [&](uint32_t address, uint32_t opcode) {
+        address &= bios.size() - 1;
+        for (int i = 0; i < 4; i++) {
+            bios[address + i] = (opcode >> (i * 8)) & 0xff;
+        }
+    };
+
+    if (config.debug.log.system) {
+        fmt::print("[INFO] Patching BIOS for system log\n");
+        patch(0x6F0C, 0x24010001);
+        patch(0x6F14, 0xAF81A9C0);
+    }
+
     return true;
 }