diff --git a/lib_com/ivas_error.h b/lib_com/ivas_error.h
index e1ba2c291250522c8cef15aebdca4201dc3dbf7a..56e09c558df56429a5be493346b7a09f46dd6bcf 100644
--- a/lib_com/ivas_error.h
+++ b/lib_com/ivas_error.h
@@ -235,7 +235,11 @@ static inline const char *ivas_error_to_string( ivas_error error_code )
         case IVAS_ERR_INVALID_HRTF:
             return "Unsupported HRTF filter set";
         case IVAS_ERR_INVALID_INPUT_FORMAT:
+#ifdef FIX_510
+            return "Invalid input format";
+#else
             return "Invalid format of input bitstream";
+#endif
         case IVAS_ERR_INVALID_INDEX:
             return "Invalid index";
         default:
diff --git a/lib_com/options.h b/lib_com/options.h
index c0f9011de9213c900b7f49dfdc95b4580b9a3f01..209a8575bcad7b8193a9d26b2c522947b6268b24 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -188,7 +188,7 @@
 #define ARITH_HUFF_CODER_CHANGES                        /* DLB: Optimization of metadata memory for Huffman and arithmetic coders */
 
 #define FIX_463_TD_RENDERER_DIRECTIVITY_RESET           /* Eri: Remove unintentional reset of directivity pattern */
-#define FIX_642											/* FhG: Fix for issue 642, buggy DoA-array access in DirAC head rotation*/
+#define FIX_642                                         /* FhG: Fix for issue 642, buggy DoA-array access in DirAC head rotation*/
 #define FIX_443_FD_CNG_INIT                             /* FhG: correct bitrate value for FD-CNG init */
 #define VARIABLE_SPEED_DECODING                         /* FhG: Contribution 37: variable speed decoding employing the JBM functioniality */
 #define JBM_TSM_ON_TCS                                  /* FhG: Contribution 37: run the TSM part of JBM on the TCs instead of the final output pcm waveforms */
@@ -224,11 +224,10 @@
 #define FIX_483                                         /* FhG: fix issue 483, division by zero in nois_est */
 #define FIX_483b                                        /* FhG: fix issue 483, uninitialized values in ivas_mct_core_enc */
 #define FIX_170_DTX_MASA                                /* Nokia: Fix issue 170, relaxing the use of DTX in MASA format */
-
+#define FIX_510                                         /* FhG: fix issue 510, misleading error message for invalid input format */
 #define FIX_509                                         /* FhG: fix issue 509, too low number of bitsream indices in SBA */
 
-
-                                                        /* ################## End DEVELOPMENT switches ######################### */
+/* ################## End DEVELOPMENT switches ######################### */
 /* clang-format on */
 
 #endif
diff --git a/lib_dec/lib_dec.c b/lib_dec/lib_dec.c
index 86ec47068072b7113bd12960b3407077660a90f9..69b6e127fdd60ab0f2c471563252528e97f2b30a 100644
--- a/lib_dec/lib_dec.c
+++ b/lib_dec/lib_dec.c
@@ -3211,7 +3211,11 @@ static ivas_error input_format_API_to_internal(
             *sdp_hf_only = 1;
             break;
         default:
+#ifdef FIX_510
+            return IVAS_ERR_INVALID_BITSTREAM;
+#else
             return IVAS_ERR_INVALID_INPUT_FORMAT;
+#endif
             break;
     }