diff --git a/algo/detectors/sts/StsReadoutConfigLegacy.cxx b/algo/detectors/sts/StsReadoutConfigLegacy.cxx
index 34f41eaef2f4bd90d81dc1ab66ba968e691614c4..d700304c2c23513152ea9cf92ac949efd80a63ca 100644
--- a/algo/detectors/sts/StsReadoutConfigLegacy.cxx
+++ b/algo/detectors/sts/StsReadoutConfigLegacy.cxx
@@ -161,10 +161,10 @@ namespace cbm::algo
           int16_t feb      = elink2Feb[elinkId];               // FEB within CROB
           if (feb != -1) {
             int16_t module = feb2module[comp][crob][feb];  // Module index
-            moduleAddress  = modAddress[module];
 
             if (module != -1) {
               assert(module < numModules);
+              moduleAddress      = modAddress[module];
               bool moduleType    = modType[module];                               // 0 or 1
               int16_t moduleSide = feb2moduleSide[comp][crob][feb];               // 0 or 1, -1 is inactive
               int16_t febType    = (moduleType == 0 ? moduleSide : !moduleSide);  // 0 = FEB A, 1 = FEB B