diff --git a/include/c128_kernal.mfk b/include/c128_kernal.mfk
index 400957fc..022e1f56 100644
--- a/include/c128_kernal.mfk
+++ b/include/c128_kernal.mfk
@@ -6,7 +6,7 @@
 
 // CHROUT. Write byte to default output. (If not screen, must call OPEN and CHKOUT beforehands.)
 // Input: A = Byte to write.
-asm void chrout(byte register(a) char) @$FFD2 !preserves_a !preserves_x !preserves_y extern
+asm void chrout(byte register(a) char) !preserves_a !preserves_x !preserves_y @$FFD2 extern
 
 asm void putchar(byte register(a) char) {
     JSR chrout
diff --git a/include/c264_kernal.mfk b/include/c264_kernal.mfk
index 1c7f92ff..42d0a4b1 100644
--- a/include/c264_kernal.mfk
+++ b/include/c264_kernal.mfk
@@ -5,7 +5,7 @@
 
 // CHROUT. Write byte to default output. (If not screen, must call OPEN and CHKOUT beforehands.)
 // Input: A = Byte to write.
-asm void chrout(byte register(a) char) @$FFD2 !preserves_a !preserves_x !preserves_y extern
+asm void chrout(byte register(a) char) !preserves_a !preserves_x !preserves_y @$FFD2 !preserves_a !preserves_x !preserves_y extern
 
 asm void putchar(byte register(a) char) {
     JSR chrout
diff --git a/include/c64_kernal.mfk b/include/c64_kernal.mfk
index 5ee723d3..8b69b668 100644
--- a/include/c64_kernal.mfk
+++ b/include/c64_kernal.mfk
@@ -2,7 +2,7 @@
 
 // CHROUT. Write byte to default output. (If not screen, must call OPEN and CHKOUT beforehands.)
 // Input: A = Byte to write.
-asm void chrout(byte register(a) char) @$FFD2 !preserves_a !preserves_x !preserves_y extern
+asm void chrout(byte register(a) char) !preserves_a !preserves_x !preserves_y @$FFD2 extern
 
 // CHRIN. Read byte from default input (for keyboard, read a line from the screen). (If not keyboard, must call OPEN and CHKIN beforehands.)
 // Output: A = Byte read.
diff --git a/include/pet_kernal.mfk b/include/pet_kernal.mfk
index bb7b7ca7..ce1220be 100644
--- a/include/pet_kernal.mfk
+++ b/include/pet_kernal.mfk
@@ -6,7 +6,7 @@
 
 // CHROUT. Write byte to default output. (If not screen, must call OPEN and CHKOUT beforehands.)
 // Input: A = Byte to write.
-asm void putchar(byte register(a) char) @$FFD2 !preserves_a !preserves_x !preserves_y extern
+asm void putchar(byte register(a) char) !preserves_a !preserves_x !preserves_y @$FFD2 extern
 
 inline void new_line() {
     putchar(13)
diff --git a/include/vic20_kernal.mfk b/include/vic20_kernal.mfk
index d6627306..5d3d9b6d 100644
--- a/include/vic20_kernal.mfk
+++ b/include/vic20_kernal.mfk
@@ -6,7 +6,7 @@
 
 // CHROUT. Write byte to default output. (If not screen, must call OPEN and CHKOUT beforehands.)
 // Input: A = Byte to write.
-asm void chrout(byte register(a) char) @$FFD2 !preserves_a !preserves_x !preserves_y extern
+asm void chrout(byte register(a) char) !preserves_a !preserves_x !preserves_y @$FFD2 extern
 
 asm void putchar(byte register(a) char) {
     JSR chrout
diff --git a/src/main/scala/millfork/env/Environment.scala b/src/main/scala/millfork/env/Environment.scala
index bc4761ca..39b4e674 100644
--- a/src/main/scala/millfork/env/Environment.scala
+++ b/src/main/scala/millfork/env/Environment.scala
@@ -2802,7 +2802,7 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
   def overlapsVariable(variable: String, expr: Expression): Boolean = {
     if (eval(expr).isDefined) return false
     if (expr.containsVariable(variable)) return true
-    val varRootName = get[Thing](variable).rootName
+    val varRootName = maybeGet[Thing](variable).getOrElse{return false}.rootName
     if (varRootName == "?") return true
     if (varRootName == "") return false
     overlapsVariableImpl(varRootName, expr)