diff --git a/silk/code_signs.c b/silk/code_signs.c
index 65187e61..02a3aeb3 100644
--- a/silk/code_signs.c
+++ b/silk/code_signs.c
@@ -54,13 +54,13 @@ void silk_encode_signs(
 
     icdf[ 1 ] = 0;
     q_ptr = pulses;
-    i = silk_SMULBB( 6, silk_ADD_LSHIFT( quantOffsetType, signalType, 1 ) );
+    i = silk_SMULBB( 7, silk_ADD_LSHIFT( quantOffsetType, signalType, 1 ) );
     icdf_ptr = &silk_sign_iCDF[ i ];
     length = silk_RSHIFT( length + SHELL_CODEC_FRAME_LENGTH/2, LOG2_SHELL_CODEC_FRAME_LENGTH );
     for( i = 0; i < length; i++ ) {
         p = sum_pulses[ i ];
         if( p > 0 ) {
-            icdf[ 0 ] = icdf_ptr[ silk_min( p - 1, 5 ) ];
+            icdf[ 0 ] = icdf_ptr[ silk_min( p & 0x1F, 6 ) ];
             for( j = 0; j < SHELL_CODEC_FRAME_LENGTH; j++ ) {
                 if( q_ptr[ j ] != 0 ) {
                     ec_enc_icdf( psRangeEnc, silk_enc_map( q_ptr[ j ]), icdf, 8 );
@@ -88,13 +88,13 @@ void silk_decode_signs(
 
     icdf[ 1 ] = 0;
     q_ptr = pulses;
-    i = silk_SMULBB( 6, silk_ADD_LSHIFT( quantOffsetType, signalType, 1 ) );
+    i = silk_SMULBB( 7, silk_ADD_LSHIFT( quantOffsetType, signalType, 1 ) );
     icdf_ptr = &silk_sign_iCDF[ i ];
     length = silk_RSHIFT( length + SHELL_CODEC_FRAME_LENGTH/2, LOG2_SHELL_CODEC_FRAME_LENGTH );
     for( i = 0; i < length; i++ ) {
         p = sum_pulses[ i ];
         if( p > 0 ) {
-            icdf[ 0 ] = icdf_ptr[ silk_min( p - 1, 5 ) ];
+            icdf[ 0 ] = icdf_ptr[ silk_min( p & 0x1F, 6 ) ];
             for( j = 0; j < SHELL_CODEC_FRAME_LENGTH; j++ ) {
                 if( q_ptr[ j ] > 0 ) {
                     /* attach sign */
diff --git a/silk/decode_pulses.c b/silk/decode_pulses.c
index 8b3fae70..692ab925 100644
--- a/silk/decode_pulses.c
+++ b/silk/decode_pulses.c
@@ -103,6 +103,8 @@ void silk_decode_pulses(
                 }
                 pulses_ptr[ k ] = abs_q;
             }
+            /* Mark the number of pulses non-zero for sign decoding. */
+            sum_pulses[ i ] |= nLS << 5;
         }
     }
 
diff --git a/silk/tables.h b/silk/tables.h
index de1fd028..1b8b68fd 100644
--- a/silk/tables.h
+++ b/silk/tables.h
@@ -63,7 +63,7 @@ extern const opus_uint8  silk_shell_code_table_offsets[ MAX_PULSES + 1 ];
 
 extern const opus_uint8  silk_lsb_iCDF[ 2 ];                                                     /*   2 */
 
-extern const opus_uint8  silk_sign_iCDF[ 36 ];                                                   /*  36 */
+extern const opus_uint8  silk_sign_iCDF[ 42 ];                                                   /*  42 */
 
 extern const opus_uint8  silk_uniform3_iCDF[ 3 ];                                                /*   3 */
 extern const opus_uint8  silk_uniform4_iCDF[ 4 ];                                                /*   4 */
diff --git a/silk/tables_pulses_per_block.c b/silk/tables_pulses_per_block.c
index 51c9e554..9859e326 100644
--- a/silk/tables_pulses_per_block.c
+++ b/silk/tables_pulses_per_block.c
@@ -254,10 +254,11 @@ const opus_uint8 silk_shell_code_table_offsets[ 17 ] = {
        135
 };
 
-const opus_uint8 silk_sign_iCDF[ 36 ] = {
-        49,     67,     77,     82,     93,     99,     11,     18,
-        24,     31,     36,     45,     46,     66,     78,     87,
-        94,    104,     14,     21,     32,     42,     51,     66,
-        94,    104,    109,    112,    115,    118,     53,     69,
-        80,     88,     95,    102
+const opus_uint8 silk_sign_iCDF[ 42 ] = {
+       254,     49,     67,     77,     82,     93,     99,
+       198,     11,     18,     24,     31,     36,     45,
+       255,     46,     66,     78,     87,     94,    104,
+       208,     14,     21,     32,     42,     51,     66,
+       255,     94,    104,    109,    112,    115,    118,
+       248,     53,     69,     80,     88,     95,    102
 };