diff --git a/include/isam.cpp b/include/isam.cpp
index cfaf1107c..783af6e7d 100755
--- a/include/isam.cpp
+++ b/include/isam.cpp
@@ -2961,7 +2961,7 @@ void TRectype::put_str(const char* fieldname, const char* val)
   if (val == NULL)
     val = "";
   if (ft == _boolfld)                            
-    val = (*val && strchr("STXY", toupper(*val)) != NULL) ? "T" : "F";
+    val = (*val && strchr("1STXY", toupper(*val)) != NULL) ? "T" : "F";
   if (*val == '\0')  // Da provare
   {
     TRecfield f(*this, fieldname);