diff --git a/firmware/main/clock_core.cpp b/firmware/main/clock_core.cpp
index 6d1b938..ec888f5 100644
--- a/firmware/main/clock_core.cpp
+++ b/firmware/main/clock_core.cpp
@@ -6,9 +6,11 @@
 
 #include "esp_expected.hpp"
 #include "clock_core_event.hpp"
+#include "string_helpers.hpp"
 
 #include <cstring>
 #include <ctime>
+#include <etl/string.h>
 
 #include <esp_event.h>
 #include <esp_log.h>
@@ -16,6 +18,8 @@
 #include <esp_netif_sntp.h>
 #include <esp_wifi.h>
 
+#include <peripherals_hal_esp.hpp>
+
 namespace
 {
 
@@ -79,9 +83,10 @@ void sntpEventHandler(struct timeval*)
   Context::getContext().events->setEvent(clock_core::EventGroup::SNTP_SYNCED);
 }
 
-void timerEventHandler(TimerHandle_t)
+void timerEventHandler(TimerHandle_t timer)
 {
-  Context::getContext().events->setEvent(clock_core::EventGroup::CLOCK_UPDATE);
+  auto context = static_cast<Context*>(pvTimerGetTimerID(timer));
+  context->events->setEvent(clock_core::EventGroup::CLOCK_UPDATE);
 }
 
 esp_err_t sntpInitialize()
@@ -136,6 +141,22 @@ std::expected<void, esp_err_t> wifiInitialize(const char* wifi_ssid, const char*
   return {};
 }
 
+etl::string<6> getCurrentTimeString()
+{
+  std::time_t time_now;
+  std::tm time_info{};
+  std::time(&time_now);
+  localtime_r(&time_now, &time_info);
+
+  etl::string<6> buffer;
+  wrapUnsafeStringOps(buffer, [&time_info](char* string, const int available)
+                      {
+                        std::strftime(string, available, "%H:%M", &time_info);
+                      });
+
+  return buffer;
+}
+
 }
 
 namespace clock_core
@@ -149,7 +170,7 @@ void run(const char* wifi_ssid, const char* wifi_password)
   auto clock_timer = xTimerCreate("clock_core",
                                   pdMS_TO_TICKS(60'000),
                                   pdTRUE,
-                                  nullptr,
+                                  &Context::getContext(),
                                   timerEventHandler);
 
   if (const auto res = wifiInitialize(wifi_ssid, wifi_password);
@@ -185,14 +206,8 @@ void run(const char* wifi_ssid, const char* wifi_password)
     }
     else if (bits & EventGroup::CLOCK_UPDATE)
     {
-      char time_buf[64];
-      std::time_t time_now;
-      std::tm time_info{};
-      std::time(&time_now);
-      localtime_r(&time_now, &time_info);
-
-      std::strftime(time_buf, sizeof(time_buf), "%c", &time_info);
-      ESP_LOGI(TAG, "Current time: %s", time_buf);
+      const auto time = getCurrentTimeString();
+      ESP_LOGI(TAG, "Current time: %s", time.c_str());
     }
     else
     {
diff --git a/firmware/main/string_helpers.hpp b/firmware/main/string_helpers.hpp
new file mode 100644
index 0000000..9955c27
--- /dev/null
+++ b/firmware/main/string_helpers.hpp
@@ -0,0 +1,16 @@
+//
+// Created by erki on 16/02/24.
+//
+
+#pragma once
+
+template<typename T, typename F>
+auto wrapUnsafeStringOps(T& string, F&& operation)
+{
+  string.initialize_free_space();
+
+  operation(string.data_end(), string.available());
+
+  string.trim_to_terminator();
+  return string;
+}
diff --git a/firmware/main/wifi_provisioner.cpp b/firmware/main/wifi_provisioner.cpp
index c406b62..bcceb65 100644
--- a/firmware/main/wifi_provisioner.cpp
+++ b/firmware/main/wifi_provisioner.cpp
@@ -88,7 +88,8 @@ esp_err_t rootPostHandler_(httpd_req_t* req)
     };
 
   etl::string<100> content_type;
-  if (const auto err = httpd_req_get_hdr_value_str(req, "Content-Type", content_type.data(), content_type.max_size() - 1);
+  content_type.initialize_free_space();
+  if (const auto err = httpd_req_get_hdr_value_str(req, "Content-Type", content_type.data_end(), content_type.available() - 1);
       err != ESP_OK)
   {
     dispatch_error("Cannot parse header.");