diff --git a/emul/forth/z80c.bin b/emul/forth/z80c.bin
index 892e604..8cb032f 100644
Binary files a/emul/forth/z80c.bin and b/emul/forth/z80c.bin differ
diff --git a/forth/boot.fs b/forth/boot.fs
index c08fb12..7abfa0e 100644
--- a/forth/boot.fs
+++ b/forth/boot.fs
@@ -65,16 +65,12 @@ PC L1 @ - A,, ( prev )
 L1 BSET ( BR )
     0x17 A,         ( nativeWord )
 L2 BSET ( used in CBR )
-    IY PUSHqq, HL POPqq, ( <-- IP )
-    E (HL) LDrr,
-    HL INCss,
-    D (HL) LDrr,
-    HL DECss,
-    DE ADDHLss,
-    HL PUSHqq, IY POPqq, ( --> IP )
+    E 0 IY+ LDrIXY,
+    D 1 IY+ LDrIXY,
+    DE ADDIYss,
     JPNEXT,
 
-NOP,  ( unused )
+NOP, NOP, NOP, NOP, ( unused )
 
 '(' A, '?' A, 'b' A, 'r' A, ')' A,
 PC L1 @ - A,, ( prev )
diff --git a/forth/z80a.fs b/forth/z80a.fs
index a9a4328..38a7fca 100644
--- a/forth/z80a.fs
+++ b/forth/z80a.fs
@@ -158,6 +158,11 @@
 0x0b OP1qq DECss,
 0x09 OP1qq ADDHLss,
 
+: ADDIXss, 0xdd A, ADDHLss, ;
+: ADDIXIX, HL ADDIXss, ;
+: ADDIYss, 0xfd A, ADDHLss, ;
+: ADDIYIY, HL ADDIYss, ;
+
 : _1rr
     C@              ( rd rr op )
     ROT             ( rr op rd )