diff --git a/docs/manual/manual_rev51.doc b/docs/manual/manual_rev51.doc
index 286c3d6..c6a0e2c 100644
Binary files a/docs/manual/manual_rev51.doc and b/docs/manual/manual_rev51.doc differ
diff --git a/docs/manual/manual_rev51.pdf b/docs/manual/manual_rev51.pdf
index 090bb82..6e7060f 100644
Binary files a/docs/manual/manual_rev51.pdf and b/docs/manual/manual_rev51.pdf differ
diff --git a/software/drsosc/DOFrame.cpp b/software/drsosc/DOFrame.cpp
index d0e3841..0c247f9 100644
--- a/software/drsosc/DOFrame.cpp
+++ b/software/drsosc/DOFrame.cpp
@@ -1359,7 +1359,7 @@ void DOFrame::OnTimer(wxTimerEvent& event)
 
          str.Printf(wxT("This board was calibrated at %1.2lg V ... %1.2lg V\nYou must recalibrate the board if you use a different input range"), 
             GetOsci()->GetCalibratedInputRange()-0.5, GetOsci()->GetCalibratedInputRange()+0.5);
-         wxMessageBox((const wxChar*)wxString::FromAscii((const char*)str), wxT("DRS Oscilloscope Warning"), wxOK | wxICON_EXCLAMATION, this);
+         wxMessageBox(str, wxT("DRS Oscilloscope Warning"), wxOK | wxICON_EXCLAMATION, this);
       }
       
       // issue warning if timing calibration not valid
diff --git a/software/drsosc/Makefile b/software/drsosc/Makefile
index 7103b5e..eca6913 100644
--- a/software/drsosc/Makefile
+++ b/software/drsosc/Makefile
@@ -29,7 +29,7 @@ OUTNAME       = drsosc
 
 # OS specific flags
 ifeq ($(OSTYPE),Darwin)
-CFLAGS        += -DOS_DARWIN -stdlib=libstdc++
+CFLAGS        += -DOS_DARWIN -stdlib=libc++
 LIBS          += -lusb-1.0
 endif