diff --git a/src/main/java/dk/camelot64/kickc/Compiler.java b/src/main/java/dk/camelot64/kickc/Compiler.java
index df45f2520..95629f117 100644
--- a/src/main/java/dk/camelot64/kickc/Compiler.java
+++ b/src/main/java/dk/camelot64/kickc/Compiler.java
@@ -93,6 +93,10 @@ public class Compiler {
       program.initAsmFragmentSynthesizer();
    }
 
+   public void initAsmFragmentSynthesizer(AsmFragmentTemplateSynthesizer synthesizer) {
+      program.initAsmFragmentSynthesizer(synthesizer);
+   }
+
    public AsmFragmentTemplateSynthesizer getAsmFragmentSynthesizer() {
       return program.getAsmFragmentSynthesizer();
    }
@@ -115,7 +119,6 @@ public class Compiler {
       }
       program.setFileName(fileName);
 
-      initAsmFragmentSynthesizer();
       try {
          Path currentPath = new File(".").toPath();
          if(this.linkScriptFileName != null) {
@@ -167,6 +170,7 @@ public class Compiler {
       new Pass1StructTypeSizeFix(program).execute();
       new Pass1AssertReturn(program).execute();
       new Pass1AssertUsedVars(program).execute();
+      new Pass1AssertNoConstParams(program).execute();
 
       if(getLog().isVerbosePass1CreateSsa()) {
          getLog().append("SYMBOLS");
diff --git a/src/main/java/dk/camelot64/kickc/model/Program.java b/src/main/java/dk/camelot64/kickc/model/Program.java
index a5092fe29..af4015512 100644
--- a/src/main/java/dk/camelot64/kickc/model/Program.java
+++ b/src/main/java/dk/camelot64/kickc/model/Program.java
@@ -203,6 +203,9 @@ public class Program {
       this.asmFragmentSynthesizer = new AsmFragmentTemplateSynthesizer(asmFragmentBaseFolder, targetCpu, asmFragmentCacheFolder, getLog());
    }
 
+   public void initAsmFragmentSynthesizer(AsmFragmentTemplateSynthesizer synthesizer) {
+      this.asmFragmentSynthesizer = synthesizer;
+   }
    public TargetCpu getTargetCpu() {
       return targetCpu;
    }
diff --git a/src/main/java/dk/camelot64/kickc/passes/Pass1AssertNoConstParams.java b/src/main/java/dk/camelot64/kickc/passes/Pass1AssertNoConstParams.java
new file mode 100644
index 000000000..27a9df8e7
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/passes/Pass1AssertNoConstParams.java
@@ -0,0 +1,30 @@
+package dk.camelot64.kickc.passes;
+
+import dk.camelot64.kickc.model.CompileError;
+import dk.camelot64.kickc.model.Program;
+import dk.camelot64.kickc.model.symbols.Procedure;
+import dk.camelot64.kickc.model.symbols.Variable;
+
+/**
+ * Check that no parameters are declared const
+ */
+public class Pass1AssertNoConstParams extends Pass1Base {
+
+   public Pass1AssertNoConstParams(Program program) {
+      super(program);
+   }
+
+   @Override
+   public boolean step() {
+      for(Procedure procedure : getScope().getAllProcedures(true)) {
+         for(Variable parameter : procedure.getParameters()) {
+            if(parameter.isDeclaredConstant()) {
+               throw new CompileError("Error! Const parameters not supported "+parameter.getName()+" in "+ procedure.getFullName()+"()");
+            }
+         }
+      }
+      return false;
+   }
+   
+}
+
diff --git a/src/test/java/dk/camelot64/kickc/test/TestPrograms.java b/src/test/java/dk/camelot64/kickc/test/TestPrograms.java
index eef8703e2..d1eea69e8 100644
--- a/src/test/java/dk/camelot64/kickc/test/TestPrograms.java
+++ b/src/test/java/dk/camelot64/kickc/test/TestPrograms.java
@@ -3,8 +3,10 @@ package dk.camelot64.kickc.test;
 import dk.camelot64.kickc.CompileLog;
 import dk.camelot64.kickc.Compiler;
 import dk.camelot64.kickc.asm.AsmProgram;
+import dk.camelot64.kickc.fragment.AsmFragmentTemplateSynthesizer;
 import dk.camelot64.kickc.model.CompileError;
 import dk.camelot64.kickc.model.Program;
+import dk.camelot64.kickc.model.TargetCpu;
 import kickass.KickAssembler;
 import kickass.nonasm.c64.CharToPetsciiConverter;
 import org.junit.AfterClass;
@@ -127,15 +129,22 @@ public class TestPrograms {
       compileAndCompare("string-pointer-problem");
    }
 
-   //@Test
-   //public void testOs52() throws IOException, URISyntaxException {
-   //   compileAndCompare("complex/unit5/os5.2");
-   //}
+/*
+   @Test
+   public void testMaze() throws IOException, URISyntaxException {
+      compileAndCompare("complex/maze/maze", log().verboseSSAOptimize());
+   }
 
-   //@Test
-   //public void testOs51() throws IOException, URISyntaxException {
-   //   compileAndCompare("complex/unit5/os5.1", log().verboseSSAOptimize());
-   //}
+   @Test
+   public void testOs52() throws IOException, URISyntaxException {
+         compileAndCompare("complex/unit5/os5.2");
+   }
+
+   @Test
+   public void testOs51() throws IOException, URISyntaxException {
+      compileAndCompare("complex/unit5/os5.1");
+   }
+*/
 
    @Test
    public void testCpu6502() throws IOException, URISyntaxException {
@@ -2406,6 +2415,11 @@ public class TestPrograms {
       compileAndCompare("const-word-pointer");
    }
 
+   @Test
+   public void testConstParam1() throws IOException, URISyntaxException {
+      assertError("const-param-1", "Error! Const parameters not supported", true);
+   }
+
    @Test
    public void testConstParam() throws IOException, URISyntaxException {
       compileAndCompare("const-param");
@@ -3242,8 +3256,13 @@ public class TestPrograms {
       compileAndCompare("condition-type-mismatch");
    }
 
+   static AsmFragmentTemplateSynthesizer asmFragmentSynthesizer;
+
    @BeforeClass
    public static void setUp() {
+      Path asmFragmentBaseFolder = new File("src/main/fragment/").toPath();
+      Path asmFragmentCacheFolder = null;
+      asmFragmentSynthesizer = new AsmFragmentTemplateSynthesizer(asmFragmentBaseFolder, TargetCpu.MOS6502X, asmFragmentCacheFolder, new CompileLog());
    }
 
    @AfterClass
@@ -3332,7 +3351,7 @@ public class TestPrograms {
       tester.testFile(filename, upliftCombinations, log);
    }
 
-   private void testFile(String fileName, Integer upliftCombinations, CompileLog compileLog) throws IOException, URISyntaxException {
+   private void testFile(String fileName, Integer upliftCombinations, CompileLog compileLog) throws IOException {
       System.out.println("Testing output for " + fileName);
       Compiler compiler = new Compiler();
       //compiler.setWarnFragmentMissing(true);
@@ -3343,6 +3362,7 @@ public class TestPrograms {
       }
       compiler.addImportPath(stdlibPath);
       compiler.addImportPath(testPath);
+      compiler.initAsmFragmentSynthesizer(asmFragmentSynthesizer);
       if(upliftCombinations != null) {
          compiler.setUpliftCombinations(upliftCombinations);
       }
diff --git a/src/test/kc/const-param-1.kc b/src/test/kc/const-param-1.kc
new file mode 100644
index 000000000..d59d33421
--- /dev/null
+++ b/src/test/kc/const-param-1.kc
@@ -0,0 +1,17 @@
+
+void main() {
+  char *maze = 0xa000;
+  word width=40;
+  word height=25;
+  ShowMaze(maze, width, height);
+}
+
+const char* SCREEN = 0x0400;
+
+void ShowMaze(const char *maze, word width, word height) {
+    char* s = SCREEN;
+    char* m = maze;
+    for( word i=0;i<width-1; i++)
+        for( word j=0;j<width-1; j++)
+            *s++ = *m++;
+}