diff --git a/engine/common/cvar.c b/engine/common/cvar.c
index 1ffa42a3..108b3956 100644
--- a/engine/common/cvar.c
+++ b/engine/common/cvar.c
@@ -519,7 +519,7 @@ void Cvar_DirectSet( convar_t *var, const char *value )
 	if( var != Cvar_FindVar( var->name ))
 		return; // how this possible?
 
-	if( FBitSet( var->flags, FCVAR_READ_ONLY|FCVAR_GLCONFIG ))
+	if( FBitSet( var->flags, FCVAR_READ_ONLY ))
 	{
 		Con_Printf( "%s is read-only.\n", var->name );
 		return;
diff --git a/ref_gl/gl_opengl.c b/ref_gl/gl_opengl.c
index a4420e83..133566de 100644
--- a/ref_gl/gl_opengl.c
+++ b/ref_gl/gl_opengl.c
@@ -355,7 +355,7 @@ qboolean GL_CheckExtension( const char *name, const dllfunc_t *funcs, const char
 	if( cvarname )
 	{
 		// system config disable extensions
-		parm = gEngfuncs.Cvar_Get( cvarname, "1", FCVAR_GLCONFIG, va( CVAR_GLCONFIG_DESCRIPTION, name ));
+		parm = gEngfuncs.Cvar_Get( cvarname, "1", FCVAR_GLCONFIG|FCVAR_READ_ONLY, va( CVAR_GLCONFIG_DESCRIPTION, name ));
 	}
 
 	if(( parm && !CVAR_TO_BOOL( parm )) || ( !CVAR_TO_BOOL( gl_extensions ) && r_ext != GL_OPENGL_110 ))
@@ -855,7 +855,7 @@ void GL_InitCommands( void )
 	r_decals = gEngfuncs.pfnGetCvarPointer( "r_decals", 0 );
 	r_showhull = gEngfuncs.pfnGetCvarPointer( "r_showhull", 0 );
 
-	gl_extensions = gEngfuncs.Cvar_Get( "gl_allow_extensions", "1", FCVAR_GLCONFIG, "allow gl_extensions" );
+	gl_extensions = gEngfuncs.Cvar_Get( "gl_allow_extensions", "1", FCVAR_GLCONFIG|FCVAR_READ_ONLY, "allow gl_extensions" );
 	gl_texture_nearest = gEngfuncs.Cvar_Get( "gl_texture_nearest", "0", FCVAR_ARCHIVE, "disable texture filter" );
 	gl_lightmap_nearest = gEngfuncs.Cvar_Get( "gl_lightmap_nearest", "0", FCVAR_ARCHIVE, "disable lightmap filter" );
 	gl_check_errors = gEngfuncs.Cvar_Get( "gl_check_errors", "1", FCVAR_ARCHIVE, "ignore video engine errors" );
@@ -871,8 +871,8 @@ void GL_InitCommands( void )
 	gl_test = gEngfuncs.Cvar_Get( "gl_test", "0", 0, "engine developer cvar for quick testing new features" );
 	gl_wireframe = gEngfuncs.Cvar_Get( "gl_wireframe", "0", FCVAR_ARCHIVE|FCVAR_SPONLY, "show wireframe overlay" );
 	gl_msaa = gEngfuncs.Cvar_Get( "gl_msaa", "1", FCVAR_ARCHIVE, "enable or disable multisample anti-aliasing" );
-	gl_stencilbits = gEngfuncs.Cvar_Get( "gl_stencilbits", "8", FCVAR_GLCONFIG, "pixelformat stencil bits (0 - auto)" );
-	gl_round_down = gEngfuncs.Cvar_Get( "gl_round_down", "2", FCVAR_GLCONFIG, "round texture sizes to nearest POT value" );
+	gl_stencilbits = gEngfuncs.Cvar_Get( "gl_stencilbits", "8", FCVAR_GLCONFIG|FCVAR_READ_ONLY, "pixelformat stencil bits (0 - auto)" );
+	gl_round_down = gEngfuncs.Cvar_Get( "gl_round_down", "2", FCVAR_GLCONFIG|FCVAR_READ_ONLY, "round texture sizes to nearest POT value" );
 	// these cvar not used by engine but some mods requires this
 	gl_polyoffset = gEngfuncs.Cvar_Get( "gl_polyoffset", "2.0", FCVAR_ARCHIVE, "polygon offset for decals" );