diff --git a/lib_com/ivas_prot_fx.h b/lib_com/ivas_prot_fx.h
index 4d150afb388dbaffa8fcb91184a130fc64840418..74ec680c49e7c064176ef8bea0c214b3dc63fcd7 100644
--- a/lib_com/ivas_prot_fx.h
+++ b/lib_com/ivas_prot_fx.h
@@ -1622,6 +1622,7 @@ void ivas_dirac_dec_output_synthesis_cov_param_mc_collect_slot_fx(
     const Word16 nchan_in                                                           /* i  : number of input channels                              */
 );
 
+#ifndef HARMONIZE_2499_CONFIGUREFDCNGDEC
 void configureFdCngDec_ivas_fx(
     HANDLE_FD_CNG_DEC hFdCngDec,                                /* i/o: Contains the variables related to the FD-based CNG process */
     const Word16 bwidth,
@@ -1630,6 +1631,7 @@ void configureFdCngDec_ivas_fx(
     const Word16 last_L_frame,
     const Word16 element_mode 
 );
+#endif
 
 void synchonize_channels_mdct_sid_fx(
     Decoder_State *sts[CPE_CHANNELS],                           /* i/o: decoder state structure                 */
diff --git a/lib_com/options.h b/lib_com/options.h
index 7f31403c939b6f3e1722deab92545bdd7034d8c2..47582491e590969bc7f270c7fa995f7bef587733 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -95,6 +95,7 @@
 #define FIX_1527_CMR_BITRATE_IDX                        /* Fix for incorrect bitrate idx packed in rtp CMR E-byte */
 #define HARMONIZE_2494_FdCng_decodeSID_fx               /* FhG: harmonize FdCng_decodeSID_fx with _ivas_ version */
 #define FIX_BASOP_2509_EVS_CONCEAL_UNINIT_MEM           /* FhG: BASOP 2509: st->hTcxCfg->psychParamsCurrent is not initialized */
+#define HARMONIZE_2499_CONFIGUREFDCNGDEC                /* FhG: basop issue 2499: harmonoize configureFdCngDec */
 
 /* #################### End BE switches ################################## */
 
diff --git a/lib_com/prot_fx.h b/lib_com/prot_fx.h
index 526512904aaaa78d9fe2810c84f4283f457529e8..913f00c66900321950a5d6d31fb20ca146ef801c 100644
--- a/lib_com/prot_fx.h
+++ b/lib_com/prot_fx.h
@@ -6510,6 +6510,7 @@ void initFdCngDec_fx(
 void deleteFdCngDec_fx(
     HANDLE_FD_CNG_DEC *hFdCngDec );
 
+#ifndef HARMONIZE_2499_CONFIGUREFDCNGDEC
 /* Configure CLDFB-CNG */
 void configureFdCngDec_fx(
     HANDLE_FD_CNG_DEC hFdCngDec, /* i/o: Contains the variables related to the CLDFB-based CNG process */
@@ -6518,6 +6519,15 @@ void configureFdCngDec_fx(
     Word16 L_frame,
     const Word16 Last_L_frame,
     const Word16 element_mode );
+#else
+void configureFdCngDec_fx(
+    HANDLE_FD_CNG_DEC hFdCngDec, /* i/o: Contains the variables related to the FD-based CNG process */
+    const Word16 bwidth,
+    const Word32 total_brate,
+    const Word16 L_frame,
+    const Word16 last_L_frame,
+    const Word16 element_mode );
+#endif
 
 Word16 ApplyFdCng_fx(
     Word16 *timeDomainInput, /* i  : pointer to time domain input */
@@ -8516,6 +8526,7 @@ void v_mult16_fx(
     const Word16 N     /* i  : Vector length                                    */
 );
 
+#ifndef HARMONIZE_2499_CONFIGUREFDCNGDEC
 void configureFdCngDec_fx(
     HANDLE_FD_CNG_DEC hFdCngDec, /* i/o: Contains the variables related to the FD-based CNG process */
     const Word16 bwidth,
@@ -8523,6 +8534,7 @@ void configureFdCngDec_fx(
     const Word16 L_frame,
     const Word16 last_L_frame,
     const Word16 element_mode );
+#endif
 
 Word32 sum2_f_16_fx(
     const Word16 *vec, /* i  : input vector                          */
diff --git a/lib_dec/core_switching_dec_fx.c b/lib_dec/core_switching_dec_fx.c
index a4badec34146c2bfceff8bbf61ab8d09d38f805e..2a7ee9fdbcb1c67571b76eb9759ae59a9e9f396e 100644
--- a/lib_dec/core_switching_dec_fx.c
+++ b/lib_dec/core_switching_dec_fx.c
@@ -1893,7 +1893,11 @@ ivas_error core_switching_pre_dec_fx(
             }
             ELSE
             {
+#ifdef HARMONIZE_2499_CONFIGUREFDCNGDEC
+                configureFdCngDec_fx( st->hFdCngDec, st->bwidth, st->total_brate, st->L_frame, st->last_L_frame, st->element_mode );
+#else
                 configureFdCngDec_ivas_fx( st->hFdCngDec, st->bwidth, st->total_brate, st->L_frame, st->last_L_frame, st->element_mode );
+#endif
             }
         }
         ELSE
diff --git a/lib_dec/fd_cng_dec_fx.c b/lib_dec/fd_cng_dec_fx.c
index aba421f957c976dee39ad86a8240cf9e41c179e6..54caafcefe758b853f23024af7a5b8e6c6e20c47 100644
--- a/lib_dec/fd_cng_dec_fx.c
+++ b/lib_dec/fd_cng_dec_fx.c
@@ -199,6 +199,7 @@ void initFdCngDec_fx(
     return;
 }
 
+#ifndef HARMONIZE_2499_CONFIGUREFDCNGDEC
 /*
    configureFdCngDec_fx
 
@@ -424,6 +425,7 @@ void configureFdCngDec_fx(
     hsCom->frameSize = shr( hsCom->fftlen, 1 );
     move16();
 }
+#endif
 
 
 /*
@@ -4279,7 +4281,11 @@ void generate_masking_noise_mdct_ivas_fx(
  *
  * Initialize an instance of type FD_CNG
  *-------------------------------------------------------------------*/
+#ifdef HARMONIZE_2499_CONFIGUREFDCNGDEC
+void configureFdCngDec_fx(
+#else
 void configureFdCngDec_ivas_fx(
+#endif
     HANDLE_FD_CNG_DEC hFdCngDec, /* i/o: Contains the variables related to the FD-based CNG process */
     const Word16 bwidth,         /*Q0*/
     const Word32 total_brate,    /*Q0*/
@@ -4306,16 +4312,13 @@ void configureFdCngDec_ivas_fx(
     ELSE IF( EQ_32( hsCom->CngBitrate, -1 ) )
     {
         /* set minimum active CBR bitrate IF CngBitrate is uninitialized */
-        IF( element_mode > EVS_MONO )
+        hsCom->CngBitrate = ACELP_7k20;
+        move32();
+        if ( GT_16( element_mode, EVS_MONO ) )
         {
             hsCom->CngBitrate = IVAS_13k2;
             move32();
         }
-        ELSE
-        {
-            hsCom->CngBitrate = ACELP_7k20;
-            move32();
-        }
     }
 
     /* FD-CNG config for MDCT-Stereo is always the same (since for > 48 kbps only) */
@@ -4464,24 +4467,31 @@ void configureFdCngDec_ivas_fx(
     hFdCngDec->nFFTpart_shaping = hFdCngDec->npart_shaping; /*Q0*/
     move16();
 
-    BASOP_getTables( &hsCom->olapWinAna, NULL, NULL, shr( hsCom->fftlen, 1 ) );
-    BASOP_getTables( &hsCom->olapWinSyn, NULL, NULL, shr( hsCom->fftlen, 2 ) );
-
     SWITCH( hsCom->fftlen )
     {
         case 512:
-            hsCom->olapWinAna_fx = olapWinAna512_fx; /*Q30*/
-            hsCom->fftSineTab_fx = NULL;
-            hsCom->olapWinSyn_fx = olapWinSyn256_fx; /*Q15*/
+#ifdef HARMONIZE_2499_CONFIGUREFDCNGDEC
+            IF( GT_16( element_mode, EVS_MONO ) )
+            {
+                hsCom->olapWinAna_fx = olapWinAna512_fx; /*Q30*/
+                hsCom->fftSineTab_fx = NULL;
+                hsCom->olapWinSyn_fx = olapWinSyn256_fx; /*Q15*/
+            }
+#endif
             hsCom->fftlenShift = 8;
             move16();
             hsCom->fftlenFac = 32767 /*1.0 Q15*/;
             move16();
             BREAK;
         case 640:
-            hsCom->olapWinAna_fx = olapWinAna640_fx; /*Q30*/
-            hsCom->fftSineTab_fx = fftSineTab640_fx; /*Q15*/
-            hsCom->olapWinSyn_fx = olapWinSyn320_fx; /*Q15*/
+#ifdef HARMONIZE_2499_CONFIGUREFDCNGDEC
+            IF( GT_16( element_mode, EVS_MONO ) )
+            {
+                hsCom->olapWinAna_fx = olapWinAna640_fx; /*Q30*/
+                hsCom->fftSineTab_fx = fftSineTab640_fx; /*Q15*/
+                hsCom->olapWinSyn_fx = olapWinSyn320_fx; /*Q15*/
+            }
+#endif
             hsCom->fftlenShift = 9;
             move16();
             hsCom->fftlenFac = 20480 /*0.625 Q15*/;
@@ -4491,6 +4501,7 @@ void configureFdCngDec_ivas_fx(
             assert( !"Unsupported FFT length for FD-based CNG" );
             BREAK;
     }
+
     BASOP_getTables( &hsCom->olapWinAna, NULL, NULL, shr( hsCom->fftlen, 1 ) );
     BASOP_getTables( &hsCom->olapWinSyn, NULL, NULL, shr( hsCom->fftlen, 2 ) );
     hsCom->frameSize = shr( hsCom->fftlen, 1 );
diff --git a/lib_dec/ivas_stereo_mdct_stereo_dec_fx.c b/lib_dec/ivas_stereo_mdct_stereo_dec_fx.c
index 654f2bd13ac191aa1f35845cc986f408926661c3..29df46c61945c957371b5f051c61feac1abcaabe 100644
--- a/lib_dec/ivas_stereo_mdct_stereo_dec_fx.c
+++ b/lib_dec/ivas_stereo_mdct_stereo_dec_fx.c
@@ -37,6 +37,9 @@
 #include "prot_fx.h"
 #include "wmc_auto.h"
 #include "ivas_prot_fx.h"
+#ifdef HARMONIZE_2499_CONFIGUREFDCNGDEC
+#include "prot_fx.h"
+#endif
 
 
 /*-------------------------------------------------------------------*
@@ -641,14 +644,22 @@ void synchonize_channels_mdct_sid_fx(
             test();
             IF( EQ_16( sts[0]->first_CNG, 1 ) && EQ_16( sts[1]->first_CNG, 0 ) )
             {
+#ifdef HARMONIZE_2499_CONFIGUREFDCNGDEC
+                configureFdCngDec_fx( st->hFdCngDec, st->bwidth, st->element_brate, st->L_frame, st->last_L_frame, st->element_mode );
+#else
                 configureFdCngDec_ivas_fx( st->hFdCngDec, st->bwidth, st->element_brate, st->L_frame, st->last_L_frame, st->element_mode );
+#endif
             }
         }
 
         IF( sts[0]->first_CNG == 0 )
         {
             /* configure CNG after reading first side info from SID to get correct values for L_frame and bwidth if first SID is also first valid frame */
+#ifdef HARMONIZE_2499_CONFIGUREFDCNGDEC
+            configureFdCngDec_fx( st->hFdCngDec, st->bwidth, st->element_brate, st->L_frame, st->last_L_frame, st->element_mode );
+#else
             configureFdCngDec_ivas_fx( st->hFdCngDec, st->bwidth, st->element_brate, st->L_frame, st->last_L_frame, st->element_mode );
+#endif
         }
     }
 
diff --git a/lib_dec/ivas_stereo_switching_dec_fx.c b/lib_dec/ivas_stereo_switching_dec_fx.c
index 59f2223d07a32f88f624c53070a4367acaebc601..554ac92bab597ab25681e7de32a9ce82e96c4cd1 100644
--- a/lib_dec/ivas_stereo_switching_dec_fx.c
+++ b/lib_dec/ivas_stereo_switching_dec_fx.c
@@ -659,8 +659,11 @@ ivas_error stereo_memory_dec_fx(
                 }
 
                 initFdCngDec_fx( st, st->cldfbSyn->scale );
-
+#ifdef HARMONIZE_2499_CONFIGUREFDCNGDEC
+                configureFdCngDec_fx( st->hFdCngDec, st->bwidth, st->total_brate, st->L_frame, st->last_L_frame, st->element_mode );
+#else
                 configureFdCngDec_ivas_fx( st->hFdCngDec, st->bwidth, st->total_brate, st->L_frame, st->last_L_frame, st->element_mode );
+#endif
             }
 
             /* allocate stereo CNG structure */