diff --git a/papers/format.md b/papers/format.md
index 7bf06da13..54c2c0275 100644
--- a/papers/format.md
+++ b/papers/format.md
@@ -1127,9 +1127,9 @@ size | description
 ## C64 compatibility note (>=187)
 
 in Furnace dev187 the volume and cutoff macros have been separated, as noted above.
-however, there's another change as well: a new, improved Special macro.
+however, there are two other changes as well: **inverted relative (non-absolute) cutoff macro**; and a new, improved Special macro.
 
-if version is less than 187, you must convert these:
+if version is less than 187, you must convert the Special macro:
 1. do not continue if ex4 is not a Sequence type macro!
 2. move bit 0 of ex4 macro data into bit 3.
 3. set bit 0 on all steps of ex4 macro to 1.
@@ -1138,6 +1138,7 @@ if version is less than 187, you must convert these:
 6. merge the ex3 macro (former Special) into ex4 (former Test).
   - use the largest size (between ex3 and ex4).
   - if the ex3 macro is shorter than the ex4 one, use the last value of ex3, and vice-versa.
+  - if the ex4 macro length is 0, expand it to the largest size, and set all steps to 1.
 
 don't worry about loop or release...
 
diff --git a/papers/newIns.md b/papers/newIns.md
index 79a8fdba2..8111ac4a4 100644
--- a/papers/newIns.md
+++ b/papers/newIns.md
@@ -327,9 +327,9 @@ size | description
 ## C64 compatibility note (>=187)
 
 in Furnace dev187 the volume and cutoff macros have been separated, as noted above.
-however, there's another change as well: a new, improved Special macro.
+however, there are two other changes as well: **inverted relative (non-absolute) cutoff macro**; and a new, improved Special macro.
 
-if version is less than 187, you must convert these:
+if version is less than 187, you must convert the Special macro:
 1. do not continue if ex4 is not a Sequence type macro!
 2. move bit 0 of ex4 macro data into bit 3.
 3. set bit 0 on all steps of ex4 macro to 1.
@@ -338,6 +338,7 @@ if version is less than 187, you must convert these:
 6. merge the ex3 macro (former Special) into ex4 (former Test).
   - use the largest size (between ex3 and ex4).
   - if the ex3 macro is shorter than the ex4 one, use the last value of ex3, and vice-versa.
+  - if the ex4 macro length is 0, expand it to the largest size, and set all steps to 1.
 
 don't worry about loop or release...
 
diff --git a/src/engine/instrument.cpp b/src/engine/instrument.cpp
index 51c2422c1..25c829ca8 100644
--- a/src/engine/instrument.cpp
+++ b/src/engine/instrument.cpp
@@ -2683,6 +2683,12 @@ DivDataErrors DivInstrument::readInsDataNew(SafeReader& reader, short version, b
     memcpy(&std.algMacro,&std.volMacro,sizeof(DivInstrumentMacro));
     std.algMacro.macroType=DIV_MACRO_ALG;
     std.volMacro=DivInstrumentMacro(DIV_MACRO_VOL,true);
+
+    if (!c64.filterIsAbs) {
+      for (int i=0; i<std.algMacro.len; i++) {
+        std.algMacro.val[i]=-std.algMacro.val[i];
+      }
+    }
   }
 
   // <187 special/test/gate merge
@@ -3429,6 +3435,12 @@ DivDataErrors DivInstrument::readInsDataOld(SafeReader &reader, short version) {
     memcpy(&std.algMacro,&std.volMacro,sizeof(DivInstrumentMacro));
     std.algMacro.macroType=DIV_MACRO_ALG;
     std.volMacro=DivInstrumentMacro(DIV_MACRO_VOL,true);
+
+    if (!c64.filterIsAbs) {
+      for (int i=0; i<std.algMacro.len; i++) {
+        std.algMacro.val[i]=-std.algMacro.val[i];
+      }
+    }
   }
 
   // <187 special/test/gate merge
@@ -3483,6 +3495,10 @@ void DivInstrument::convertC64SpecialMacro() {
       for (int i=std.ex4Macro.len; i<maxLen; i++) {
         std.ex4Macro.val[i]=std.ex3Macro.val[std.ex4Macro.len-1];
       }
+    } else {
+      for (int i=0; i<maxLen; i++) {
+        std.ex4Macro.val[i]=1;
+      }
     }
     for (int i=0; i<maxLen; i++) {
       if (i>=std.ex3Macro.len) {