diff --git a/libsrc/apple2/uppercasemask.s b/libsrc/apple2/uppercasemask.s
index 8b993bb1e..b0f05eee7 100644
--- a/libsrc/apple2/uppercasemask.s
+++ b/libsrc/apple2/uppercasemask.s
@@ -4,6 +4,25 @@
 
         .export         uppercasemask
 
+        .ifndef __APPLE2ENH__
+        .import         machinetype
+        .constructor    detectlowercase
+        .endif
+
+        .ifndef __APPLE2ENH__
+
+        .segment "ONCE"
+
+detectlowercase:
+        bit     machinetype
+        bpl     :+
+
+        lda     #$FF
+        sta     uppercasemask
+:       rts
+
+        .endif
+
         .data
 
 uppercasemask:  .byte   $DF     ; Convert to uppercase