diff --git a/libs/emulator/include/emulator/ShiftRegister.h b/libs/emulator/include/emulator/ShiftRegister.h
index 0da1702..56f743e 100644
--- a/libs/emulator/include/emulator/ShiftRegister.h
+++ b/libs/emulator/include/emulator/ShiftRegister.h
@@ -2,27 +2,31 @@
 
 #include "core/Base.h"
 
+enum class ShiftRegisterMode {
+    // There are actually more modes, but I think Vectrex only uses these ones
+    Disabled,
+    ShiftOutUnder02,
+};
+
+
 // The VIA's shift register, mainly responsible for driving the drawing of line patterns. It can be
 // loaded with an 8 bit mask that represents the pattern to be drawn, and although it's called a
 // "shift" register, it actually rotates its values so the pattern will repeat.
 class ShiftRegister {
 public:
+    void SetMode(ShiftRegisterMode mode) { m_mode = mode; }
+    ShiftRegisterMode Mode() const { return m_mode; }
+
     void SetValue(uint8_t value);
     uint8_t ReadValue() const;
     bool CB2Active() const { return m_cb2Active; }
-    bool Enabled() const {
-        // For now, always return true as it seems the shift register isn't disabled by games on
-        // Vectrex. Also, am not sure exactly how to control the enabled state of the shift
-        // register; I believe it may be controlled by bit 4 of the VIA's auxiliary control register
-        // ($B).
-        return true;
-    }
     void Update(cycles_t cycles);
 
     void SetInterruptFlag(bool enabled) { m_interruptFlag = enabled; }
     bool InterruptFlag() const { return m_interruptFlag; }
 
 private:
+    ShiftRegisterMode m_mode = ShiftRegisterMode::Disabled;
     uint8_t m_value = 0;
     mutable int m_shiftCyclesLeft = 0;
     bool m_cb2Active = false;
diff --git a/libs/emulator/src/Via.cpp b/libs/emulator/src/Via.cpp
index 24c5679..44fdf72 100644
--- a/libs/emulator/src/Via.cpp
+++ b/libs/emulator/src/Via.cpp
@@ -5,11 +5,6 @@
 #include "emulator/MemoryMap.h"
 
 namespace {
-    enum class ShiftRegisterMode {
-        // There are actually many more modes, but I think Vectrex only uses one
-        ShiftOutUnder02
-    };
-
     namespace Register {
         enum Type {
             PortB = 0x0,
@@ -51,10 +46,14 @@ namespace {
         inline ShiftRegisterMode GetShiftRegisterMode(uint8_t auxCntrl) {
             uint8_t result =
                 ReadBitsWithShift(auxCntrl, ShiftRegisterModeMask, ShiftRegisterModeShift);
-            if (result != 0b110) {
-                ErrorHandler::Unsupported(
-                    "ShiftRegisterMode expected to only support ShiftOutUnder02\n");
+            switch (result) {
+            case 0:
+                return ShiftRegisterMode::Disabled;
+            case 0b110:
+                return ShiftRegisterMode::ShiftOutUnder02;
             }
+            ErrorHandler::Unsupported(
+                "Unexpected ShiftRegisterMode: 0x%X, forcing to ShiftOutUnder02\n", result);
             return ShiftRegisterMode::ShiftOutUnder02;
         }
 
@@ -209,8 +208,7 @@ void Via::DoSync(cycles_t cycles, const Input& input, RenderContext& renderConte
         m_shiftRegister.Update(cycles);
 
         // Shift register's CB2 line drives /BLANK
-        //@TODO: check some flag on the shift register to know whether it's active
-        if (m_shiftRegister.Enabled()) {
+        if (m_shiftRegister.Mode() == ShiftRegisterMode::ShiftOutUnder02) {
             m_screen.SetBlankEnabled(m_shiftRegister.CB2Active());
         }
 
@@ -425,9 +423,7 @@ void Via::Write(uint16_t address, uint8_t value) {
         break;
 
     case Register::AuxCntl: {
-        // For now just read the shift register mode, which will assert if it's invalid/unexpected
-        auto shiftRegisterMode = AuxCntl::GetShiftRegisterMode(value);
-        (void)shiftRegisterMode;
+        m_shiftRegister.SetMode(AuxCntl::GetShiftRegisterMode(value));
 
         ASSERT_MSG(AuxCntl::GetTimer1Mode(value) == TimerMode::OneShot,
                    "t1 assumed always on one-shot mode");
@@ -450,7 +446,7 @@ void Via::Write(uint16_t address, uint8_t value) {
                    "Top 2 bits should always be 1 (right?)");
 
         m_periphCntl = value;
-        if (!m_shiftRegister.Enabled()) {
+        if (m_shiftRegister.Mode() == ShiftRegisterMode::Disabled) {
             m_screen.SetBlankEnabled(PeriphCntl::IsBlankEnabled(m_periphCntl));
         }
     } break;