diff --git a/Makefile b/Makefile
index 008bf8c..bd14c7d 100644
--- a/Makefile
+++ b/Makefile
@@ -2,8 +2,8 @@
 
 all : mandel.xex
 
-mandel.xex : mandel.o tables.o
-	ld65 -C ./atari-asm-xex.cfg -o $@ $+
+mandel.xex : mandel.o tables.o atari-asm-xex.cfg
+	ld65 -C ./atari-asm-xex.cfg -o $@ mandel.o tables.o
 
 %.o : %.s
 	ca65 -o $@ $<
diff --git a/atari-asm-xex.cfg b/atari-asm-xex.cfg
index 6e6498d..fb43089 100644
--- a/atari-asm-xex.cfg
+++ b/atari-asm-xex.cfg
@@ -6,7 +6,8 @@ SYMBOLS {
 }
 MEMORY {
     ZP:      file = "", define = yes, start = $0082, size = $007E;
-    MAIN:    file = %O, define = yes, start = %S,    size = $BC20 - %S;
+    #MAIN:    file = %O, define = yes, start = %S,    size = $BC20 - %S;
+    MAIN:    file = %O, define = yes, start = %S,    size = $4000 - %S;
 }
 FILES {
     %O: format = atari;
diff --git a/mandel.s b/mandel.s
index 9eb6ce1..7bfb577 100644
--- a/mandel.s
+++ b/mandel.s
@@ -375,11 +375,11 @@ viewport_oy:
 .endmacro
 
 .macro sqr16_round dest, arg, shift
-    imul16_round dest, arg, arg, shift
-    ;copy16 FR0, arg   ; 12 cyc
-    ;jsr sqr16_func      ; ? cyc
-    ;shift_round_16 FR2, shift
-    ;copy16 dest, FR2 + 2  ; 12 cyc
+    ;imul16_round dest, arg, arg, shift
+    copy16 FR0, arg   ; 12 cyc
+    jsr sqr16_func      ; ? cyc
+    shift_round_16 FR2, shift
+    copy16 dest, FR2 + 2  ; 12 cyc
 .endmacro
 
 ; clobbers a, x