diff --git a/src/d3d9/d3d9_constant_layout.h b/src/d3d9/d3d9_constant_layout.h
index ddee0f3b..df4120bc 100644
--- a/src/d3d9/d3d9_constant_layout.h
+++ b/src/d3d9/d3d9_constant_layout.h
@@ -14,7 +14,12 @@ namespace dxvk {
 
     uint32_t floatSize()     const { return floatCount   * 4 * sizeof(float); }
     uint32_t intSize()       const { return intCount     * 4 * sizeof(int); }
-    uint32_t bitmaskSize()   const { return bitmaskCount * 1 * sizeof(uint32_t); }
+    uint32_t bitmaskSize()   const {
+      // Account for SWVP (non SWVP uses a spec constant)
+      return bitmaskCount != 1
+        ? bitmaskCount * 1 * sizeof(uint32_t)
+        : 0;
+    }
 
     uint32_t floatOffset()   const { return 0; }
     uint32_t intOffset()     const { return floatOffset() + floatSize(); }
diff --git a/src/d3d9/d3d9_device.cpp b/src/d3d9/d3d9_device.cpp
index e03881af..7c8a7e80 100644
--- a/src/d3d9/d3d9_device.cpp
+++ b/src/d3d9/d3d9_device.cpp
@@ -4438,8 +4438,6 @@ namespace dxvk {
       std::memcpy(dst->fConsts, Src.fConsts, constSet.meta->maxConstIndexF * sizeof(Vector4));
     if (constSet.meta->maxConstIndexI)
       std::memcpy(dst->iConsts, Src.iConsts, constSet.meta->maxConstIndexI * sizeof(Vector4i));
-    if (constSet.meta->maxConstIndexB)
-      dst->bConsts[0] = Src.bConsts[0];
   }
 
 
@@ -5422,9 +5420,18 @@ namespace dxvk {
           GetVertexShaderPermutation());
       }
       UploadConstants<DxsoProgramTypes::VertexShader>();
+
+      if (likely(!CanSWVP())) {
+        UpdateBoolSpecConstantVertex(
+          m_state.vsConsts.bConsts[0] &
+          GetCommonShader(m_state.vertexShader)->GetMeta().boolConstantMask);
+      } else
+        UpdateBoolSpecConstantVertex(0);
     }
-    else
+    else {
+      UpdateBoolSpecConstantVertex(0);
       UpdateFixedFunctionVS();
+    }
 
     if (m_flags.test(D3D9DeviceFlag::DirtyInputLayout))
       BindInputLayout();
@@ -5444,8 +5451,13 @@ namespace dxvk {
         UpdateSamplerTypes(m_d3d9Options.forceSamplerTypeSpecConstants ? m_samplerTypeBitfield : 0u, 0u);
       else
         UpdateSamplerTypes(m_samplerTypeBitfield, m_projectionBitfield); // For implicit samplers...
+
+      UpdateBoolSpecConstantPixel(
+        m_state.psConsts.bConsts[0] &
+        GetCommonShader(m_state.pixelShader)->GetMeta().boolConstantMask);
     }
     else {
+      UpdateBoolSpecConstantPixel(0);
       UpdateSamplerTypes(0u, 0u);
 
       UpdateFixedFunctionPS();
@@ -5764,7 +5776,8 @@ namespace dxvk {
       ? DetermineMaxCount(m_state.vertexShader)
       : DetermineMaxCount(m_state.pixelShader);
 
-    m_consts[ProgramType].dirty |= StartRegister < maxCount;
+    if constexpr (ConstantType != D3D9ConstantType::Bool)
+      m_consts[ProgramType].dirty |= StartRegister < maxCount;
 
     UpdateStateConstants<ProgramType, ConstantType, T>(
       &m_state,
@@ -6104,6 +6117,30 @@ namespace dxvk {
   }
 
 
+  void D3D9DeviceEx::UpdateBoolSpecConstantVertex(uint32_t value) {
+    if (value == m_lastBoolSpecConstantVertex)
+      return;
+
+    EmitCs([cBitfield = value](DxvkContext* ctx) {
+      ctx->setSpecConstant(VK_PIPELINE_BIND_POINT_GRAPHICS, D3D9SpecConstantId::VertexShaderBools, cBitfield);
+      });
+
+    m_lastBoolSpecConstantVertex = value;
+  }
+
+
+  void D3D9DeviceEx::UpdateBoolSpecConstantPixel(uint32_t value) {
+    if (value == m_lastBoolSpecConstantPixel)
+      return;
+
+    EmitCs([cBitfield = value](DxvkContext* ctx) {
+      ctx->setSpecConstant(VK_PIPELINE_BIND_POINT_GRAPHICS, D3D9SpecConstantId::PixelShaderBools, cBitfield);
+      });
+
+    m_lastBoolSpecConstantPixel = value;
+  }
+
+
   void D3D9DeviceEx::UpdateSamplerSpecConsant(uint32_t value) {
     EmitCs([cBitfield = value](DxvkContext* ctx) {
       ctx->setSpecConstant(VK_PIPELINE_BIND_POINT_GRAPHICS, D3D9SpecConstantId::SamplerType, cBitfield);
@@ -6484,6 +6521,8 @@ namespace dxvk {
     m_flags.set(D3D9DeviceFlag::DirtyInputLayout);
 
     UpdateSamplerSpecConsant(0u);
+    UpdateBoolSpecConstantVertex(0u);
+    UpdateBoolSpecConstantPixel(0u);
 
     return D3D_OK;
   }
diff --git a/src/d3d9/d3d9_device.h b/src/d3d9/d3d9_device.h
index d8968657..6c919311 100644
--- a/src/d3d9/d3d9_device.h
+++ b/src/d3d9/d3d9_device.h
@@ -1014,6 +1014,9 @@ namespace dxvk {
     uint32_t                        m_lastProjectionBitfield = 0;
     uint32_t                        m_projectionBitfield = 0;
 
+    uint32_t                        m_lastBoolSpecConstantVertex = 0;
+    uint32_t                        m_lastBoolSpecConstantPixel  = 0;
+
     uint32_t                        m_lastPointMode = 0;
 
     uint32_t                        m_activeRTs        = 0;
@@ -1162,6 +1165,10 @@ namespace dxvk {
 
     bool UseProgrammablePS();
 
+    void UpdateBoolSpecConstantVertex(uint32_t value);
+
+    void UpdateBoolSpecConstantPixel(uint32_t value);
+
     void UpdateSamplerSpecConsant(uint32_t value);
 
     void UpdateProjectionSpecConstant(uint32_t value);
diff --git a/src/d3d9/d3d9_spec_constants.h b/src/d3d9/d3d9_spec_constants.h
index cdd04a63..5d1bd3c0 100644
--- a/src/d3d9/d3d9_spec_constants.h
+++ b/src/d3d9/d3d9_spec_constants.h
@@ -14,6 +14,9 @@ namespace dxvk {
 
     PointMode       = 6,
     ProjectionType  = 7,
+
+    VertexShaderBools = 8,
+    PixelShaderBools  = 9,
   };
 
 }
\ No newline at end of file
diff --git a/src/dxso/dxso_compiler.cpp b/src/dxso/dxso_compiler.cpp
index 4acc3b63..306e9a38 100644
--- a/src/dxso/dxso_compiler.cpp
+++ b/src/dxso/dxso_compiler.cpp
@@ -294,10 +294,9 @@ namespace dxvk {
     m_module.decorateArrayStride(members[0], 16);
     m_module.decorateArrayStride(members[1], 16);
 
-    if (m_layout->bitmaskCount == 1) {
-      members[2] = getScalarTypeId(DxsoScalarType::Uint32);
-    }
-    else {
+    const bool swvp = m_layout->bitmaskCount != 1;
+
+    if (swvp) {
       // Must be a multiple of 4 otherwise.
       members[2] = m_module.defArrayTypeUnique(
         getVectorTypeId({ DxsoScalarType::Uint32, 4 }),
@@ -307,18 +306,22 @@ namespace dxvk {
     }
 
     const uint32_t structType =
-      m_module.defStructType(members.size(), members.data());
+      m_module.defStructType(swvp ? 3 : 2, members.data());
 
     m_module.decorateBlock(structType);
 
     m_module.memberDecorateOffset(structType, 0, m_layout->floatOffset());
     m_module.memberDecorateOffset(structType, 1, m_layout->intOffset());
-    m_module.memberDecorateOffset(structType, 2, m_layout->bitmaskOffset());
+
+    if (swvp)
+      m_module.memberDecorateOffset(structType, 2, m_layout->bitmaskOffset());
 
     m_module.setDebugName(structType, "cbuffer_t");
     m_module.setDebugMemberName(structType, 0, "f");
     m_module.setDebugMemberName(structType, 1, "i");
-    m_module.setDebugMemberName(structType, 2, "b");
+
+    if (swvp)
+      m_module.setDebugMemberName(structType, 2, "b");
 
     m_cBuffer = m_module.newVar(
       m_module.defPointerType(structType, spv::StorageClassUniform),
@@ -339,6 +342,13 @@ namespace dxvk {
     resource.view   = VK_IMAGE_VIEW_TYPE_MAX_ENUM;
     resource.access = VK_ACCESS_UNIFORM_READ_BIT;
     m_resourceSlots.push_back(resource);
+
+    m_boolSpecConstant = m_module.specConst32(m_module.defIntType(32, 0), 0);
+    m_module.decorateSpecId(m_boolSpecConstant, getSpecId(
+      m_programInfo.type() == DxsoProgramType::VertexShader
+      ? D3D9SpecConstantId::VertexShaderBools
+      : D3D9SpecConstantId::PixelShaderBools));
+    m_module.setDebugName(m_boolSpecConstant, "boolConstants");
   }
 
 
@@ -897,6 +907,7 @@ namespace dxvk {
       case DxsoRegisterType::ConstBool:
         m_meta.maxConstIndexB = std::max(m_meta.maxConstIndexB, reg.id.num + 1);
         m_meta.maxConstIndexB = std::min(m_meta.maxConstIndexB, m_layout->boolCount);
+        m_meta.boolConstantMask |= 1 << reg.id.num;
         break;
       
       default: break;
@@ -939,18 +950,25 @@ namespace dxvk {
       uint32_t uintType  = getScalarTypeId(DxsoScalarType::Uint32);
       uint32_t uvec4Type = getVectorTypeId({ DxsoScalarType::Uint32, 4 });
 
-      std::array<uint32_t, 2> indices = { m_module.constu32(2), m_module.constu32(reg.id.num / 128) };
+      // If not SWVP, spec const this
+      uint32_t bitfield;
+      if (m_layout->bitmaskCount != 1) {
+        std::array<uint32_t, 2> indices = { m_module.constu32(2), m_module.constu32(reg.id.num / 128) };
 
-      uint32_t indexCount = m_layout->bitmaskCount == 1 ? 1 : 2;
-      uint32_t accessType = m_layout->bitmaskCount == 1 ? uintType : uvec4Type;
+        uint32_t indexCount = m_layout->bitmaskCount == 1 ? 1 : 2;
+        uint32_t accessType = m_layout->bitmaskCount == 1 ? uintType : uvec4Type;
 
-      uint32_t ptrId = m_module.opAccessChain(
-        m_module.defPointerType(accessType, spv::StorageClassUniform),
-        m_cBuffer, indexCount, indices.data());
+        uint32_t ptrId = m_module.opAccessChain(
+          m_module.defPointerType(accessType, spv::StorageClassUniform),
+          m_cBuffer, indexCount, indices.data());
+
+        bitfield = m_module.opLoad(accessType, ptrId);
+      }
+      else
+        bitfield = m_boolSpecConstant;
 
       uint32_t bitIdx = m_module.consti32(reg.id.num % 32);
 
-      uint32_t bitfield = m_module.opLoad(accessType, ptrId);
       if (m_layout->bitmaskCount != 1) {
         uint32_t index = (reg.id.num % 128) / 32;
         bitfield = m_module.opCompositeExtract(uintType, bitfield, 1, &index);
diff --git a/src/dxso/dxso_compiler.h b/src/dxso/dxso_compiler.h
index 4185f335..b46ff682 100644
--- a/src/dxso/dxso_compiler.h
+++ b/src/dxso/dxso_compiler.h
@@ -266,6 +266,8 @@ namespace dxvk {
 
     SpirvModule                m_module;
 
+    uint32_t                   m_boolSpecConstant;
+
     ///////////////////////////////////////////////////////
     // Resource slot description for the shader. This will
     // be used to map D3D9 bindings to DXVK bindings.
diff --git a/src/dxso/dxso_isgn.h b/src/dxso/dxso_isgn.h
index 168c8d8e..2faa04ef 100644
--- a/src/dxso/dxso_isgn.h
+++ b/src/dxso/dxso_isgn.h
@@ -34,6 +34,8 @@ namespace dxvk {
     uint32_t maxConstIndexF = 0;
     uint32_t maxConstIndexI = 0;
     uint32_t maxConstIndexB = 0;
+
+    uint32_t boolConstantMask = 0;
   };
 
 }
\ No newline at end of file