diff --git a/assembler.js b/assembler.js
index de50abe..be49a6c 100644
--- a/assembler.js
+++ b/assembler.js
@@ -86,7 +86,8 @@ function decodeInstructions(line) {
     // Handle constant definitions
     if (opName.startsWith('=')) {
       // TODO: validate constant
-      let constantName = opName.substring(1); // strip '>'
+      // FIXME - a quick hack to get around problems caused by another use of lower-casing to sanitize input:
+      let constantName = opName.substring(1).toLowerCase(); // strip '>'
       let constantValue = arg_str;
       constants[constantName] = constantValue;
       dbg(2, `constants:`);
@@ -125,7 +126,8 @@ function decodeInstructions(line) {
 
     // Handle references to constants
     } else if (arg_str.startsWith('=')) {
-      arg_str = arg_str.substring(1) // strip '>'
+      // FIXME - a quick hack to get around problems caused by another use of lower-casing to sanitize input:
+      arg_str = arg_str.substring(1).toLowerCase(); // strip '>'
       dbg(2, `operand references '${arg_str}'`);
       arg_str = constants[arg_str];
       dbg(2, `arg_str from '${arg_str}`);