diff --git a/CMakeLists.txt b/CMakeLists.txt
index fa356a6..6a5a0ef 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,6 +15,7 @@ if(NOT EXISTS ${LIBAVR_ROOT}/CMakeLists.txt)
 	message(FATAL_ERROR "libavr not found at ${LIBAVR_ROOT} - run: git submodule update --init libavr")
 endif()
 add_subdirectory(${LIBAVR_ROOT} libavr-build)
+include(${LIBAVR_ROOT}/cmake/checks.cmake)
 
 add_executable(fantemp src/main.cpp)
 target_link_libraries(fantemp PRIVATE libavr)
diff --git a/libavr b/libavr
index 99434fb..1412b71 160000
--- a/libavr
+++ b/libavr
@@ -1 +1 @@
-Subproject commit 99434fb29af18f219ba9d24ba22d4d068e5790bb
+Subproject commit 1412b7173b5c343d225cced990473f5e6b510c32
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 551b543..e48917b 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -1,3 +1,5 @@
+libavr_format_test()
+
 # The battery is a compile: a static_assert that fails is the failure. It is a
 # target rather than only a ctest so a plain build catches a regression too.
 add_library(consteval_tests OBJECT consteval.cpp)
diff --git a/test/consteval.cpp b/test/consteval.cpp
index b152034..176d87a 100644
--- a/test/consteval.cpp
+++ b/test/consteval.cpp
@@ -58,9 +58,9 @@ static_assert(curve_rises());
 // definition puts that count at the nominal temperature.
 using app::thermistor::detail::quarters_entry;
 
-inline constexpr std::int32_t nominal_count = static_cast<std::int32_t>(
-    app::thermistor::adc_full_scale * app::thermistor::nominal_resistance /
-    (app::thermistor::series_resistor + app::thermistor::nominal_resistance));
+inline constexpr std::int32_t nominal_count =
+    static_cast<std::int32_t>(app::thermistor::adc_full_scale * app::thermistor::nominal_resistance /
+                              (app::thermistor::series_resistor + app::thermistor::nominal_resistance));
 static_assert(quarters_entry(nominal_count / 4) >= 100);    // 25.00 C, in quarters
 static_assert(quarters_entry(nominal_count / 4 + 1) < 100); // and the step below it