diff --git a/src/Targets/RiscV/IsaDescriptor.cpp b/src/Targets/RiscV/IsaDescriptor.cpp
index 4106a43d..a7524407 100644
--- a/src/Targets/RiscV/IsaDescriptor.cpp
+++ b/src/Targets/RiscV/IsaDescriptor.cpp
@@ -141,9 +141,11 @@ namespace Targets::RiscV
                 if (character == '_') {
                     commitMultiLetterExtension(*multiLetterExtension);
                     multiLetterExtension = std::nullopt;
+
+                } else {
+                    multiLetterExtension->push_back(character);
                 }
 
-                multiLetterExtension->push_back(character);
                 ++stringOffset;
                 continue;
             }