diff --git a/tycho-testing-harness/src/main/java/org/eclipse/tycho/test/AbstractTychoIntegrationTest.java b/tycho-testing-harness/src/main/java/org/eclipse/tycho/test/AbstractTychoIntegrationTest.java
index 5254ea12d8..b6c8ba3508 100644
--- a/tycho-testing-harness/src/main/java/org/eclipse/tycho/test/AbstractTychoIntegrationTest.java
+++ b/tycho-testing-harness/src/main/java/org/eclipse/tycho/test/AbstractTychoIntegrationTest.java
@@ -92,6 +92,7 @@ protected Verifier getVerifier(String test, boolean setTargetPlatform, File user
         verifier.setForkJvm(isForked());
         if (isDisableMirrors()) {
             verifier.setSystemProperty("tycho.disableP2Mirrors", "true");
+            verifier.setSystemProperty("eclipse.p2.mirrors", "false");
         }
         String debug = System.getProperty("tycho.mvnDebug");
         if (debug != null) {