diff --git a/src/common/db2.h b/src/common/db2.h
index e383dcc..4860046 100644
--- a/src/common/db2.h
+++ b/src/common/db2.h
@@ -207,6 +207,25 @@ struct db2 {
                 }
                 return ja;
             }
+            void load_from_json(const path &fn) {
+                auto ja = nlohmann::json::parse(read_file(fn));
+                for (auto &&[tn,t] : ja.items()) {
+                    for (auto &&[vn,v] : t.items()) {
+                        for (auto &&[fn, fv] : v.items()) {
+                            if (0) {
+                            } else if (fv.is_number_integer()) {
+                                m[tn][vn][fn] = fv.get<int>();
+                            } else if (fv.is_number_float()) {
+                                m[tn][vn][fn] = fv.get<float>();
+                            } else if (fv.is_string()) {
+                                m[tn][vn][fn] = fv.get<std::string>();
+                            } else {
+                                throw std::runtime_error{"bad json type"};
+                            }
+                        }
+                    }
+                }
+            }
             void save(const path &fn, int codepage = 1251) {
                 auto s_to_char20 = [&](char20 &dst, const std::string &in, int codepage = 1251) {
                     auto s = utf8_to_dbstr(in);
diff --git a/src/db_extractor2/db_extractor2.cpp b/src/db_extractor2/db_extractor2.cpp
index 6a84bf7..d5d8386 100644
--- a/src/db_extractor2/db_extractor2.cpp
+++ b/src/db_extractor2/db_extractor2.cpp
@@ -31,15 +31,22 @@
 
 int main(int argc, char *argv[])
 {
-    cl::opt<path> db_fn(cl::Positional, cl::desc("<db file>"), cl::Required);
+    cl::opt<path> db_fn(cl::Positional, cl::desc("<db file or json file to backwards conversion>"), cl::Required);
 
     cl::ParseCommandLineOptions(argc, argv);
 
-    db2 db{db_fn};
-    auto f = db.open();
-    auto m = f.to_map();
-    write_file(path{db_fn} += ".json", m.to_json().dump(1));
-    m.save(path{db_fn} += "new");
+    path fn = db_fn;
+    fn = fs::absolute(fn);
+    if (fn.extension() != ".json") {
+        db2 db{fn};
+        auto f = db.open();
+        auto m = f.to_map();
+        write_file(path{fn} += ".json", m.to_json().dump(1));
+    } else {
+        db2::files::db2_internal db;
+        db.load_from_json(fn);
+        db.save(fn.parent_path() / fn.stem());
+    }
 
     return 0;
 }