diff --git a/src/hwapi.cpp b/src/hwapi.cpp
index 8027197..035f73e 100644
--- a/src/hwapi.cpp
+++ b/src/hwapi.cpp
@@ -59,8 +59,10 @@ hwapi::hwapi(QWidget *parent) : QObject(parent)
         qCritical() << "Creating/attaching shared memory failed";
     }
 
-    Q_ASSERT_X(sizeof(SharedMem) != m_sharedMem->size(),
-               "compare sizes", "sizes different");
+    Q_ASSERT_X(sizeof(SharedMem) == m_sharedMem->size(), "check shm-sizes",
+               QString("sizes different %1 != %2")
+                .arg(sizeof(SharedMem))
+                .arg(m_sharedMem->size()).toStdString().c_str());
 
     //if (shdMem_firstUse())        // für Master raus
 //    {
@@ -3351,7 +3353,6 @@ void hwapi::sys_restoreDeviceParameter(struct T_devices *deviceSettings) const
         *start = buf[nn];
         start++;
     } while(++nn<LL);
-
 }
 
 bool hwapi::sys_areDCdataValid(void) const
@@ -4442,8 +4443,8 @@ bool hwapi::dcDownloadRequest(QString const &dcFileToDownload) const {
 bool hwapi::dcDownloadRequested() const {
     SharedMem *data = SharedMem::getData();
     Q_ASSERT_X(data != nullptr, "check", "pointer invalid");
-    Q_ASSERT_X((void *)data != m_sharedMem->data(), "compare pointers", "pointers different");
-    Q_ASSERT_X(sizeof(*data) != m_sharedMem->size(), "compare sizes", "sizes different");
+    Q_ASSERT_X((void *)data == m_sharedMem->data(), "compare pointers", "pointers different");
+    Q_ASSERT_X(sizeof(*data) == m_sharedMem->size(), "compare sizes", "sizes different");
 
     // called by download-thread
     // 1: true at entry: reset atomically to false