diff --git a/assembler.js b/assembler.js
index be49a6c..96a3893 100644
--- a/assembler.js
+++ b/assembler.js
@@ -137,6 +137,8 @@ function decodeInstructions(line) {
       addressingMode = "indirect";
       arg_str = arg_str.replace("(=", "");
       arg_str = arg_str.replace(")", "");
+      // FIXME - a quick hack to get around problems caused by another use of lower-casing to sanitize input:
+      arg_str = arg_str.toLowerCase();
       dbg(2, `INDY - operand references '${arg_str}'`);
       arg_str = constants[arg_str];