diff --git a/lib_com/options.h b/lib_com/options.h
index 556b6f79b027a4be7bea4c59bc71d2f96a5b495c..6f7547635813c3274c3b1520ddce7e9868539340 100755
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -220,6 +220,8 @@
 
 #define COMPLEXITY_LEVEL_INDICATION
 
+#define FIX_642											/* FhG: Fix for issue 642, buggy DoA-array access in DirAC head rotation*/
+
 #define VARIABLE_SPEED_DECODING                         /* FhG: variable speed decoding employing the JBM functioniality */
 #define JBM_TSM_ON_TCS                                  /* FhG: run the TSM part of JBM on the TCs instead of the final output pcm waveforms */
 
diff --git a/lib_dec/ivas_dirac_dec.c b/lib_dec/ivas_dirac_dec.c
index 861b7da54545d30ba6ca1f56cc9fd47e39d4a9df..cb7c9f5b9afe00a869f2a6d93fcadef4e3caa299 100644
--- a/lib_dec/ivas_dirac_dec.c
+++ b/lib_dec/ivas_dirac_dec.c
@@ -2922,6 +2922,7 @@ void ivas_dirac_dec_render_sf(
 #endif
 #ifdef JBM_TSM_ON_TCS
     /* Another workaround for self test BE */
+#ifndef FIX_642
     if ( st_ivas->hHeadTrackData && st_ivas->hDecoderConfig->voip_active == 0 )
     {
         QuatToRotMat( st_ivas->hHeadTrackData->Quaternions[st_ivas->hHeadTrackData->num_quaternions++], st_ivas->hHeadTrackData->Rmat );
@@ -2942,6 +2943,7 @@ void ivas_dirac_dec_render_sf(
     {
         p_Rmat = 0;
     }
+#endif
 
     /* copy parameters into local buffers*/
 
@@ -2976,7 +2978,11 @@ void ivas_dirac_dec_render_sf(
     }
 
 #ifdef JBM_TSM_ON_TCS
-    if ( st_ivas->hHeadTrackData && st_ivas->hDecoderConfig->voip_active == 1 )
+    if ( st_ivas->hHeadTrackData
+#ifndef FIX_642
+         && st_ivas->hDecoderConfig->voip_active == 1
+#endif
+    )
 #else
         if ( st_ivas->hHeadTrackData )
 #endif
@@ -2996,7 +3002,6 @@ void ivas_dirac_dec_render_sf(
             {
 #ifdef JBM_TSM_ON_TCS
                 rotateAziEle_DirAC( azimuth[slot_idx], elevation[slot_idx], num_freq_bands, hDirAC->num_freq_bands, p_Rmat );
-
 #else
                     /* note, this seems wrong since it does not take the dirac read ptr into account */
                     index_slot = subframe_idx * hDirAC->subframe_nbslots + slot_idx;
@@ -3006,7 +3011,7 @@ void ivas_dirac_dec_render_sf(
             }
         }
     }
-#ifdef JBM_TSM_ON_TCS
+#if defined( JBM_TSM_ON_TCS ) & !defined( FIX_642 )
     else if ( !st_ivas->hHeadTrackData )
 #else
         else