diff --git a/libavr b/libavr
index b62d6b5..8521f48 160000
--- a/libavr
+++ b/libavr
@@ -1 +1 @@
-Subproject commit b62d6b5b30b1122128b1d277c715f92aeb2abcff
+Subproject commit 8521f48a3361100c5f3e3c5004a5ff415e2d1484
diff --git a/pureboot b/pureboot
index 6ba53fb..07b4790 160000
--- a/pureboot
+++ b/pureboot
@@ -1 +1 @@
-Subproject commit 6ba53fb2fa22d4c3d93ab5ddaae3356db394c627
+Subproject commit 07b47905cad7e60137a37b3a2cc9741facf0a48e
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 10dceb6..5f38153 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -20,13 +20,15 @@ add_test(NAME fantemp.consteval
 # The board has no reset line and no programming header, so the loader-entry
 # route in the emitted image is the only thing standing between a firmware change
 # and an unreflashable board.
-find_package(Python3 COMPONENTS Interpreter)
-if(Python3_FOUND)
-	add_test(NAME fantemp.reachability
-	         COMMAND ${Python3_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/check_reachability.py
-	                 --objdump ${CMAKE_OBJDUMP} --elf $<TARGET_FILE:fantemp>
-	                 --image $<TARGET_FILE_DIR:fantemp>/fantemp.bin
-	                 --loader-base ${PUREBOOT_BASE_HEX})
-else()
-	message(STATUS "Python not found - the reachability check is skipped")
-endif()
+# A check whose interpreter this host lacks is registered and *skips*, rather
+# than leaving the suite a different size on a different machine - which is a
+# suite nothing can be compared against. The launcher and the marker are
+# libavr's (`cmake/checks.cmake`).
+libavr_launcher(_python "${LIBAVR_NO_PYTHON}" ${Python3_EXECUTABLE})
+add_test(NAME fantemp.reachability
+         COMMAND ${_python} ${CMAKE_CURRENT_SOURCE_DIR}/check_reachability.py
+                 --objdump ${CMAKE_OBJDUMP} --elf $<TARGET_FILE:fantemp>
+                 --image $<TARGET_FILE_DIR:fantemp>/fantemp.bin
+                 --loader-base ${PUREBOOT_BASE_HEX})
+
+libavr_skip_unverified()