diff --git a/src/pse/gpu.cpp b/src/pse/gpu.cpp
index 5a8345250..4d89e420e 100644
--- a/src/pse/gpu.cpp
+++ b/src/pse/gpu.cpp
@@ -614,7 +614,7 @@ bool GPU::HandleFillRectangleCommand()
   if (m_GP0_command.size() < 3)
     return false;
 
-  const u32 color = (m_GP0_command[0] & UINT32_C(0x00FFFFFF)) | UINT32_C(0xFF000000);
+  const u32 color = m_GP0_command[0] & UINT32_C(0x00FFFFFF);
   const u32 dst_x = m_GP0_command[1] & UINT32_C(0xFFFF);
   const u32 dst_y = m_GP0_command[1] >> 16;
   const u32 width = m_GP0_command[2] & UINT32_C(0xFFFF);
@@ -622,7 +622,11 @@ bool GPU::HandleFillRectangleCommand()
 
   Log_DebugPrintf("Fill VRAM rectangle offset=(%u,%u), size=(%u,%u)", dst_x, dst_y, width, height);
 
-  FillVRAM(dst_x, dst_y, width, height, color);
+  // Drop higher precision when filling. Bit15 is set to 0.
+  // TODO: Force 8-bit color option.
+  const u16 color16 = RGBA8888ToRGBA5551(color);
+
+  FillVRAM(dst_x, dst_y, width, height, color16);
   return true;
 }
 
@@ -735,7 +739,7 @@ void GPU::UpdateDisplay()
 
 void GPU::ReadVRAM(u32 x, u32 y, u32 width, u32 height, void* buffer) {}
 
-void GPU::FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color) {}
+void GPU::FillVRAM(u32 x, u32 y, u32 width, u32 height, u16 color) {}
 
 void GPU::UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data) {}
 
diff --git a/src/pse/gpu.h b/src/pse/gpu.h
index d5fd4025c..78335516f 100644
--- a/src/pse/gpu.h
+++ b/src/pse/gpu.h
@@ -166,7 +166,7 @@ protected:
   // Rendering in the backend
   virtual void UpdateDisplay();
   virtual void ReadVRAM(u32 x, u32 y, u32 width, u32 height, void* buffer);
-  virtual void FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color);
+  virtual void FillVRAM(u32 x, u32 y, u32 width, u32 height, u16 color);
   virtual void UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data);
   virtual void CopyVRAM(u32 src_x, u32 src_y, u32 dst_x, u32 dst_y, u32 width, u32 height);
   virtual void DispatchRenderCommand(RenderCommand rc, u32 num_vertices);
diff --git a/src/pse/gpu_hw_opengl.cpp b/src/pse/gpu_hw_opengl.cpp
index c0691832b..3e11c8aa3 100644
--- a/src/pse/gpu_hw_opengl.cpp
+++ b/src/pse/gpu_hw_opengl.cpp
@@ -230,14 +230,14 @@ void GPU_HW_OpenGL::ReadVRAM(u32 x, u32 y, u32 width, u32 height, void* buffer)
   }
 }
 
-void GPU_HW_OpenGL::FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color)
+void GPU_HW_OpenGL::FillVRAM(u32 x, u32 y, u32 width, u32 height, u16 color)
 {
   glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer_fbo_id);
 
   glEnable(GL_SCISSOR_TEST);
   glScissor(x, VRAM_HEIGHT - y - height, width, height);
 
-  const auto [r, g, b, a] = RGBA8ToFloat(color);
+  const auto [r, g, b, a] = RGBA8ToFloat(RGBA5551ToRGBA8888(color));
   glClearColor(r, g, b, a);
   glClear(GL_COLOR_BUFFER_BIT);
 }
diff --git a/src/pse/gpu_hw_opengl.h b/src/pse/gpu_hw_opengl.h
index 3c5cb6df3..fba9a28ae 100644
--- a/src/pse/gpu_hw_opengl.h
+++ b/src/pse/gpu_hw_opengl.h
@@ -19,7 +19,7 @@ public:
 protected:
   void UpdateDisplay() override;
   void ReadVRAM(u32 x, u32 y, u32 width, u32 height, void* buffer) override;
-  void FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color) override;
+  void FillVRAM(u32 x, u32 y, u32 width, u32 height, u16 color) override;
   void UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data) override;
   void CopyVRAM(u32 src_x, u32 src_y, u32 dst_x, u32 dst_y, u32 width, u32 height) override;
   void UpdateTexturePageTexture() override;