diff --git a/mx.trufflesqueak/mx_trufflesqueak.py b/mx.trufflesqueak/mx_trufflesqueak.py
index 2c21f7682..4338b965c 100644
--- a/mx.trufflesqueak/mx_trufflesqueak.py
+++ b/mx.trufflesqueak/mx_trufflesqueak.py
@@ -101,32 +101,16 @@ def _add_unit_tests(tasks, supports_coverage):
             mx_unittest.unittest(unittest_args)
 
 
-# Extend `vmArgs` with `_get_runtime_jvm_args` when running `mx unittest`
 def _unittest_config_participant(config):
-    vmArgs, mainClass, mainClassArgs = config
-    jdk = mx.get_jdk(tag='default')
-    runtime_args = _get_runtime_jvm_args(jdk)
-    # Remove the cp argument from the runtime args
-    cp = None
-    for i, cp in enumerate(runtime_args[:]):
-        if cp == '-cp':
-            cp = runtime_args[i + 1]
-            runtime_args.remove('-cp')
-            runtime_args.remove(cp)
-            break
-    # Attach remaining runtime args
-    vmArgs += runtime_args
-    # Merge the classpaths
-    if cp:
-        for i, arg in enumerate(vmArgs):
-            if arg == '-cp':
-                vmArgs[i + 1] += ':' + cp
-    config = (vmArgs, mainClass, mainClassArgs)
-    return config
-
+    (vmArgs, mainClass, mainClassArgs) = config
+    vmArgs += ['-Dpolyglotimpl.DisableClassPathIsolation=true']
+    mainClassArgs += ['-JUnitOpenPackages', 'de.hpi.swa.trufflesqueak/*=de.hpi.swa.trufflesqueak.test']
+    mainClassArgs += ['-JUnitOpenPackages', 'de.hpi.swa.trufflesqueak/*=ALL-UNNAMED']
+    return (vmArgs, mainClass, mainClassArgs)
 
 mx_unittest.add_config_participant(_unittest_config_participant)
 
+mx_truffle.should_add_tck_participant(False)
 
 def _add_tck_tests(tasks, supports_coverage):
     with mx_gate.Task('TruffleSqueak TCK tests', tasks, tags=['test']) as t:
diff --git a/mx.trufflesqueak/suite.py b/mx.trufflesqueak/suite.py
index 992742669..5eb89c9c9 100644
--- a/mx.trufflesqueak/suite.py
+++ b/mx.trufflesqueak/suite.py
@@ -363,7 +363,7 @@
             "distDependencies": ["TRUFFLESQUEAK"],
             "testDistribution": True,
             "maven" : False,
-            "useModulePath": False,
+            "useModulePath": True,
         },
     },
 }