diff --git a/.github/workflows/unix.yml b/.github/workflows/unix.yml
index 4352624da4..8fe774ada7 100644
--- a/.github/workflows/unix.yml
+++ b/.github/workflows/unix.yml
@@ -117,6 +117,7 @@ jobs:
       BUILDCACHE_LUA_PATH: ${{ github.workspace }}/tools
       BUILDCACHE_DIR: ${{ github.workspace }}/.buildcache
       BUILDCACHE_MAX_CACHE_SIZE: 1073741824
+      BUILDCACHE_DEBUG: 1
       UBSAN_OPTIONS: halt_on_error=1:abort_on_error=1
       ASAN_OPTIONS: alloc_dealloc_mismatch=0
       CLICOLOR_FORCE: 1
diff --git a/.pkg b/.pkg
index e909a7b565..328947cbfe 100644
--- a/.pkg
+++ b/.pkg
@@ -101,7 +101,7 @@
 [nigiri]
   url=git@github.com:motis-project/nigiri.git
   branch=master
-  commit=e8c8f8ed2aa3ff3bf8cd556e7b161ae3ae0b13dc
+  commit=260eff7fa7751cbf601357f4b8632133a9277733
 [osmium]
   url=git@github.com:motis-project/libosmium.git
   branch=master
diff --git a/.pkg.lock b/.pkg.lock
index 59951db763..f6613be29b 100644
--- a/.pkg.lock
+++ b/.pkg.lock
@@ -1,4 +1,4 @@
-11298868496727142457
+15622830898542171340
 cista a6218e9cd9da9e1c7a70c1188e2faf9e082b7f1c
 zlib fe8e13ffca867612951bc6baf114e5ac8b00f305
 boost be5235eb2258d2ec19e32546ab767a62311d9b46
@@ -29,7 +29,7 @@ abseil-cpp f2b3825f36e37fddd47c5c395096e9b1e99eca12
 protobuf 690e03babf0963d3da9615a2dae0891777842719
 unordered_dense 4f380fb1d64f1843ca2c993ed39a8342a8747e5d
 wyhash 1e012b57fc2227a9e583a57e2eacb3da99816d99
-nigiri e8c8f8ed2aa3ff3bf8cd556e7b161ae3ae0b13dc
+nigiri 260eff7fa7751cbf601357f4b8632133a9277733
 lua 7bb93325b26f84c7e8b51fcbd857361ce7605a1d
 luabind 9223568bbcf818ecfb1001d49f567627ee10852a
 tbb 2067af88257710d07253761655a802732a32496e
diff --git a/modules/nigiri/include/motis/nigiri/nigiri.h b/modules/nigiri/include/motis/nigiri/nigiri.h
index 09c8487ea1..4903e52503 100644
--- a/modules/nigiri/include/motis/nigiri/nigiri.h
+++ b/modules/nigiri/include/motis/nigiri/nigiri.h
@@ -45,6 +45,7 @@ struct nigiri : public motis::module::module {
   std::vector<std::string> gtfsrt_paths_;
   unsigned gtfsrt_update_interval_sec_{60U};
   bool gtfsrt_incremental_{false};
+  bool debug_{false};
 };
 
 }  // namespace motis::nigiri
diff --git a/modules/nigiri/src/nigiri.cc b/modules/nigiri/src/nigiri.cc
index bb7daef0e7..b30d8125ae 100644
--- a/modules/nigiri/src/nigiri.cc
+++ b/modules/nigiri/src/nigiri.cc
@@ -1,5 +1,7 @@
 #include "motis/nigiri/nigiri.h"
 
+#include <fstream>
+
 #include "boost/filesystem.hpp"
 
 #include "cista/memory_holder.h"
@@ -19,6 +21,7 @@
 #include "nigiri/rt/create_rt_timetable.h"
 #include "nigiri/rt/gtfsrt_update.h"
 #include "nigiri/rt/rt_timetable.h"
+#include "nigiri/rt/util.h"
 #include "nigiri/timetable.h"
 
 #include "motis/core/common/logging.h"
@@ -137,6 +140,7 @@ nigiri::nigiri() : module("Next Generation Routing", "nigiri") {
         "list of GTFS-RT, format: tag|/path/to/file.pb");
   param(gtfsrt_incremental_, "gtfsrt_incremental",
         "true=incremental updates, false=forget all prev. RT updates");
+  param(debug_, "debug", "write protobuf JSON files for debugging");
 }
 
 nigiri::~nigiri() = default;
@@ -309,8 +313,13 @@ void nigiri::update_gtfsrt() {
     auto const tag = impl_->tags_.get_tag_clean(endpoint.src());
     auto stats = n::rt::statistics{};
     try {
+      auto const& body = f->val().body;
+      if (debug_) {
+        std::ofstream{fmt::format("{}/{}.json", get_data_directory(), tag)}
+            << n::rt::protobuf_to_json(body);
+      }
       stats = n::rt::gtfsrt_update_buf(**impl_->tt_, *rtt, endpoint.src(), tag,
-                                       f->val().body);
+                                       body);
     } catch (std::exception const& e) {
       stats.parser_error_ = true;
       LOG(logging::error) << "GTFS-RT update error (tag=" << tag << ") "