diff --git a/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentManager.java b/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentManager.java
index d78c46e87..6dae5d94f 100644
--- a/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentManager.java
+++ b/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentManager.java
@@ -115,6 +115,7 @@ public class AsmFragmentManager {
       synths.add(new FragmentSynthesis("zpsby1=(.*)", ".*=.*zpsby1.*", null, "asby=$1", "sta {zpsby1}\n", mapZpsby));
       synths.add(new FragmentSynthesis("_deref_cowo1=(.*)", null, null, "aby=$1", "sta {cowo1}\n", mapConst));
       synths.add(new FragmentSynthesis("_deref_zpptrby1=(.*)", ".*=.*zpptrby1.*", null, "aby=$1", "ldy #0\n" + "sta ({zpptrby1}),y\n", mapZpptrby));
+      synths.add(new FragmentSynthesis("cowo1_derefidx_zpby1=(.*)", null, null, "aby=$1", "ldx {zpby1}\n"+"sta {cowo1},x\n", mapZpby));
 
       synths.add(new FragmentSynthesis("(.*)=xby(.*)", ".*=.*as?by.*", "txa\n", "$1=aby$2", null, null));
       synths.add(new FragmentSynthesis("(.*)=yby(.*)", ".*=.*as?by.*", "tya\n", "$1=aby$2", null, null));
diff --git a/src/main/java/dk/camelot64/kickc/fragment/asm/aby=_byte_xsby.asm b/src/main/java/dk/camelot64/kickc/fragment/asm/aby=_byte_xsby.asm
new file mode 100644
index 000000000..403ee3380
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/fragment/asm/aby=_byte_xsby.asm
@@ -0,0 +1 @@
+txa
\ No newline at end of file
diff --git a/src/main/java/dk/camelot64/kickc/fragment/asm/aby=_byte_ysby.asm b/src/main/java/dk/camelot64/kickc/fragment/asm/aby=_byte_ysby.asm
new file mode 100644
index 000000000..8b4b4f7e8
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/fragment/asm/aby=_byte_ysby.asm
@@ -0,0 +1 @@
+tya
\ No newline at end of file
diff --git a/src/main/java/dk/camelot64/kickc/fragment/asm/cowo1_derefidx_zpby1=zpby2.asm b/src/main/java/dk/camelot64/kickc/fragment/asm/cowo1_derefidx_zpby1=zpby2.asm
deleted file mode 100644
index c02c4dccd..000000000
--- a/src/main/java/dk/camelot64/kickc/fragment/asm/cowo1_derefidx_zpby1=zpby2.asm
+++ /dev/null
@@ -1,3 +0,0 @@
-lda {zpby2}
-ldx {zpby1}
-sta {cowo1},x
\ No newline at end of file
diff --git a/src/main/java/dk/camelot64/kickc/fragment/asm/xby=_byte_asby.asm b/src/main/java/dk/camelot64/kickc/fragment/asm/xby=_byte_asby.asm
new file mode 100644
index 000000000..ec799692e
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/fragment/asm/xby=_byte_asby.asm
@@ -0,0 +1 @@
+tax
\ No newline at end of file
diff --git a/src/main/java/dk/camelot64/kickc/fragment/asm/xby=_byte_ysby.asm b/src/main/java/dk/camelot64/kickc/fragment/asm/xby=_byte_ysby.asm
new file mode 100644
index 000000000..916220eb0
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/fragment/asm/xby=_byte_ysby.asm
@@ -0,0 +1,2 @@
+sty $ff
+ldx $ff
\ No newline at end of file
diff --git a/src/main/java/dk/camelot64/kickc/fragment/asm/xby=_byte_zpsby1.asm b/src/main/java/dk/camelot64/kickc/fragment/asm/xby=_byte_zpsby1.asm
new file mode 100644
index 000000000..a49c6c9e2
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/fragment/asm/xby=_byte_zpsby1.asm
@@ -0,0 +1 @@
+ldx {zpsby1}
\ No newline at end of file
diff --git a/src/main/java/dk/camelot64/kickc/fragment/asm/yby=_byte_asby.asm b/src/main/java/dk/camelot64/kickc/fragment/asm/yby=_byte_asby.asm
new file mode 100644
index 000000000..7e4499cf3
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/fragment/asm/yby=_byte_asby.asm
@@ -0,0 +1 @@
+tay
\ No newline at end of file
diff --git a/src/main/java/dk/camelot64/kickc/fragment/asm/yby=_byte_xsby.asm b/src/main/java/dk/camelot64/kickc/fragment/asm/yby=_byte_xsby.asm
new file mode 100644
index 000000000..989559d4c
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/fragment/asm/yby=_byte_xsby.asm
@@ -0,0 +1,2 @@
+stx $ff
+ldy $ff
\ No newline at end of file
diff --git a/src/main/java/dk/camelot64/kickc/fragment/asm/yby=_byte_zpsby1.asm b/src/main/java/dk/camelot64/kickc/fragment/asm/yby=_byte_zpsby1.asm
new file mode 100644
index 000000000..0d3be70ce
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/fragment/asm/yby=_byte_zpsby1.asm
@@ -0,0 +1 @@
+ldy {zpsby1}
\ No newline at end of file