diff --git a/GPU/GLES/ShaderManagerGLES.cpp b/GPU/GLES/ShaderManagerGLES.cpp
index a4b43c14cc..388403736a 100644
--- a/GPU/GLES/ShaderManagerGLES.cpp
+++ b/GPU/GLES/ShaderManagerGLES.cpp
@@ -845,6 +845,11 @@ LinkedShader *ShaderManagerGLES::ApplyFragmentShader(ShaderID VSID, Shader *vs,
 	shaderSwitchDirtyUniforms_ = 0;
 
 	if (ls == nullptr) {
+		_dbg_assert_(G3D, FSID.Bit(FS_BIT_LMODE) == VSID.Bit(VS_BIT_LMODE));
+		_dbg_assert_(G3D, FSID.Bit(FS_BIT_DO_TEXTURE) == VSID.Bit(VS_BIT_DO_TEXTURE));
+		_dbg_assert_(G3D, FSID.Bit(FS_BIT_ENABLE_FOG) == VSID.Bit(VS_BIT_ENABLE_FOG));
+		_dbg_assert_(G3D, FSID.Bit(FS_BIT_FLATSHADE) == VSID.Bit(VS_BIT_FLATSHADE));
+
 		// Check if we can link these.
 		ls = new LinkedShader(VSID, vs, FSID, fs, vs->UseHWTransform());
 		ls->use(VSID, lastShader_);
diff --git a/GPU/GPUState.h b/GPU/GPUState.h
index c67db91dfe..f2941e8f34 100644
--- a/GPU/GPUState.h
+++ b/GPU/GPUState.h
@@ -60,7 +60,7 @@ struct GPUgstate {
 				lightEnable[4],
 				clipEnable,
 				cullfaceEnable,
-				textureMapEnable,
+				textureMapEnable,  // 0x1E GE_CMD_TEXTUREMAPENABLE
 				fogEnable,
 				ditherEnable,
 				alphaBlendEnable,
@@ -116,8 +116,8 @@ struct GPUgstate {
 				materialspecularcoef, // 0x5B
 				ambientcolor,         // 0x5C
 				ambientalpha,         // 0x5D
-				lmode,                // 0x5E
-				ltype[4],             // 0x5F-0x62
+				lmode,                // 0x5E      GE_CMD_LIGHTMODE
+				ltype[4],             // 0x5F-0x62 GE_CMD_LIGHTTYPEx
 				lpos[12],             // 0x63-0x6E
 				ldir[12],             // 0x6F-0x7A
 				latt[12],             // 0x7B-0x86
@@ -141,7 +141,7 @@ struct GPUgstate {
 				texsize[8],           // 0xB8-BF
 				texmapmode,           // 0xC0
 				texshade,             // 0xC1
-				texmode,              // 0xC2
+				texmode,              // 0xC2 GE_CMD_TEXMODE
 				texformat,            // 0xC3
 				loadclut,             // 0xC4
 				clutformat,           // 0xC5
@@ -158,7 +158,7 @@ struct GPUgstate {
 				texlodslope,          // 0xD0
 				padxxxxxx,            // 0xD1
 				framebufpixformat,    // 0xD2
-				clearmode,            // 0xD3
+				clearmode,            // 0xD3 GE_CMD_CLEARMODE
 				scissor1,
 				scissor2,
 				minz,
diff --git a/GPU/Vulkan/ShaderManagerVulkan.cpp b/GPU/Vulkan/ShaderManagerVulkan.cpp
index db8b14f990..36b03aee8d 100644
--- a/GPU/Vulkan/ShaderManagerVulkan.cpp
+++ b/GPU/Vulkan/ShaderManagerVulkan.cpp
@@ -239,6 +239,11 @@ void ShaderManagerVulkan::GetShaders(int prim, u32 vertType, VulkanVertexShader
 		FSID = lastFSID_;
 	}
 
+	_dbg_assert_(G3D, FSID.Bit(FS_BIT_LMODE) == VSID.Bit(VS_BIT_LMODE));
+	_dbg_assert_(G3D, FSID.Bit(FS_BIT_DO_TEXTURE) == VSID.Bit(VS_BIT_DO_TEXTURE));
+	_dbg_assert_(G3D, FSID.Bit(FS_BIT_ENABLE_FOG) == VSID.Bit(VS_BIT_ENABLE_FOG));
+	_dbg_assert_(G3D, FSID.Bit(FS_BIT_FLATSHADE) == VSID.Bit(VS_BIT_FLATSHADE));
+
 	// Just update uniforms if this is the same shader as last time.
 	if (lastVShader_ != nullptr && lastFShader_ != nullptr && VSID == lastVSID_ && FSID == lastFSID_) {
 		*vshader = lastVShader_;