diff --git a/lib_com/hp50_fx.c b/lib_com/hp50_fx.c
old mode 100644
new mode 100755
index d6a1182a4e9aa45305e27197e88260cf78d0d7e2..7a63914f69bce71fb7f3be319e284bb1aa5b1a70
--- a/lib_com/hp50_fx.c
+++ b/lib_com/hp50_fx.c
@@ -338,6 +338,9 @@ void hp20( Word16 signal[],     /* i/o: signal to filter                   any *
     return;
 }
 
+/* Can be moved to options.h */
+//#define HP20_FIX32_RECODING
+//#define DEBUG_hp20
 
 #ifdef HP20_FIX32_RECODING
 void hp20_fx_32(
@@ -347,8 +350,8 @@ void hp20_fx_32(
     const Word32 Fs )
 {
     Word32 i;
-    Word32 a1_fx, a2_fx, b1_fx, b2_fx;
-    Word32 diff_pos, diff_neg;
+    Word32 a1_fx, a2_fx, b1_fx, b2_fx, signal_fx_i;
+    Word16 diff_pos, diff_neg;
 #ifndef ISSUE_1836_replace_overflow_libcom
     Flag Overflow = 0;
 #endif
@@ -369,16 +372,23 @@ void hp20_fx_32(
 #endif
 
 
-    diff = L_max( diff_pos, diff_neg );
+    diff = s_min( diff_pos, diff_neg );
 
     IF( NE_16( diff, 0 ) )
     {
+#ifdef DEBUG_hp20
+        printf( "diff1: %d  diff_pos=%d  diff_neg=%d  mem_fx[2]=0x%08X  mem_fx[3]=0x%08X  prescale=%d prescaleOld=%d\n", diff, diff_pos, diff_neg, mem_fx[2], mem_fx[3], prescale, prescaleOld );
+#endif
         prescale = s_min( prescale, diff );
     }
 
     prescale = s_min( 3, sub( 1 + HP20_COEFF_SCALE, prescale ) );
 
     diff = sub( prescale, prescaleOld );
+#ifdef DEBUG_hp20
+    printf( "diff2: %d  prescale=%d prescaleOld=%d\n", diff, prescale, prescaleOld );
+#endif
+
 #ifdef ISSUE_1836_replace_overflow_libcom
     mem_fx[0] = L_shr_sat( mem_fx[0], diff );
     move32();
@@ -451,6 +461,11 @@ void hp20_fx_32(
     Word64 W_sum, W_y0, W_y1, W_y2;
     Word32 x0, x1, x2;
 
+#ifdef DEBUG_hp20
+    printf( "a1=0x%08X  a2=0x%08X  --  b1=0x%08X  b2=0x%08X\n", a1_fx, a2_fx, b1_fx, b2_fx );
+    printf( "diff3: Prescale: %d (prescale_current_frame=%d)\n", getScaleFactor32( signal_fx, lg ), prescale_current_frame );
+#endif
+
     W_sum = W_mult_32_32( b2_fx, mem_fx[2] );       /* b2*x2 */
     W_sum = W_mac_32_32( W_sum, b1_fx, mem_fx[3] ); /* b1*x1 */
     x2 = L_shr( signal_fx[0], prescale );
@@ -458,8 +473,12 @@ void hp20_fx_32(
     W_sum = W_mac_32_32( W_sum, mem_fx[0], a2_fx ); /* y2*a2 */
     W_sum = W_mac_32_32( W_sum, mem_fx[1], a1_fx ); /* y1*a1 */
     W_y2 = W_shl( W_sum, HP20_COEFF_SCALE );
-    signal_fx[0] = W_extract_h( W_shl( W_y2, prescale ) );
+    signal_fx_i = W_extract_h( W_shl( W_y2, prescale ) );
+    signal_fx[0] = signal_fx_i;
     move32();
+#ifdef DEBUG_hp20
+    printf( "signal[%3d] = 0x%08X (0x%016llX << %d = 0x%016llX)\n", 0, signal_fx[0], W_y2, prescale, W_shl( W_y2, prescale ) );
+#endif
 
     W_sum = W_mult_32_32( b2_fx, mem_fx[3] ); /* b2*x2 */
     W_sum = W_mac_32_32( W_sum, b1_fx, x2 );  /* b1*x1 */
@@ -468,8 +487,12 @@ void hp20_fx_32(
     W_sum = W_mac_32_32( W_sum, mem_fx[1], a2_fx );           /* y2*a2 */
     W_sum = W_mac_32_32( W_sum, W_extract_h( W_y2 ), a1_fx ); /* y1*a1 */
     W_y1 = W_shl( W_sum, HP20_COEFF_SCALE );
-    signal_fx[1] = W_extract_h( W_shl( W_y1, prescale ) );
+    signal_fx_i = W_extract_h( W_shl( W_y1, prescale ) );
+    signal_fx[1] = signal_fx_i;
     move32();
+#ifdef DEBUG_hp20
+    printf( "signal[%3d] = 0x%08X (0x%016llX << %d = 0x%016llX)\n", 1, signal_fx[1], W_y1, prescale, W_shl( W_y1, prescale ) );
+#endif
 
     diff = sub( prescale_current_frame, prescale );
     W_y1 = W_shr( W_y1, diff );
@@ -487,8 +510,12 @@ void hp20_fx_32(
         W_sum = W_mac_32_32( W_sum, W_extract_h( W_y1 ), a1_fx ); /* y1*a1 */
         W_y0 = W_shl( W_sum, HP20_COEFF_SCALE );
 
-        signal_fx[i] = W_extract_h( W_shl( W_y0, prescale_current_frame ) );
+        signal_fx_i = W_extract_h( W_shl( W_y0, prescale_current_frame ) );
+        signal_fx[i] = signal_fx_i;
         move32();
+#ifdef DEBUG_hp20
+        printf( "signal[%3d] = 0x%08X (0x%016llX << %d = 0x%016llX)\n", i, signal_fx[i], W_y0, prescale_current_frame, W_shl( W_y0, prescale_current_frame ) );
+#endif
 
         x2 = x1;
         x1 = x0;
@@ -521,7 +548,7 @@ void hp20_fx_32(
     const Word32 Fs )
 {
     Word16 i;
-    Word32 a1_fx, a2_fx, b1_fx, b2_fx;
+    Word32 a1_fx, a2_fx, b1_fx, b2_fx, signal_fx_i;
     Word16 Qx0, Qx1, Qx2, Qy1, Qprev_y1, Qy2, Qprev_y2, Qmin;
     Word64 x0_fx64, x1_fx64, x2_fx64, y0_fx64, y1_fx64, y2_fx64, R1, R2, R3, R4, R5;
 
@@ -574,6 +601,11 @@ void hp20_fx_32(
     move32();
     move32();
 
+#ifdef DEBUG_hp20
+    printf( "a1=0x%08X  a2=0x%08X  --  b1=0x%08X  b2=0x%08X\n", a1_fx, a2_fx, b1_fx, b2_fx );
+    printf( "Prescale: %d\n", getScaleFactor32( signal_fx, lg ) );
+#endif
+
     Qprev_y1 = extract_l( mem_fx[4] );
     Qprev_y2 = extract_l( mem_fx[5] );
     y1_fx64 = W_deposit32_l( mem_fx[0] );
@@ -648,13 +680,16 @@ void hp20_fx_32(
 
         y0_fx64 = W_shr( y0_fx64, 29 );
 
-        signal_fx[i] = W_extract_l( W_shr( y0_fx64, Qmin ) );
-        move32();
-        IF( signal_fx[i] < 0 )
+        signal_fx_i = W_extract_l( W_shr( y0_fx64, Qmin ) );
+        if ( signal_fx_i < 0 )
         {
-            signal_fx[i] = L_add( signal_fx[i], 1 );
-            move32();
+            signal_fx_i = L_add( signal_fx_i, 1 );
         }
+        signal_fx[i] = signal_fx_i;
+        move32();
+#ifdef DEBUG_hp20
+        printf( "signal[%3d] = 0x%08X (0x%016llX >> %d = 0x%016llX)\n", i, signal_fx[i], y0_fx64, Qmin, W_shr( y0_fx64, Qmin ) );
+#endif
 
         y2_fx64 = y1_fx64;
         y1_fx64 = y0_fx64;
@@ -689,6 +724,10 @@ void hp20_fx_32(
     mem_fx[4] = Qprev_y1;
     mem_fx[5] = Qprev_y2;
 
+#ifdef DEBUG_hp20
+    printf( "Headroom: %d\n", getScaleFactor32( signal_fx, lg ) );
+#endif
+
     move32();
     move32();
     move32();