diff --git a/Sming/Core/HardwareTimer.h b/Sming/Core/HardwareTimer.h
index bf3677e0a2..92c9327fbc 100644
--- a/Sming/Core/HardwareTimer.h
+++ b/Sming/Core/HardwareTimer.h
@@ -141,11 +141,10 @@ class Timer1Api : public CallbackTimerApi<Timer1Api<clkdiv, mode>>
 template <hw_timer_clkdiv_t clkdiv, HardwareTimerMode mode> uint8_t Timer1Api<clkdiv, mode>::state;
 template <hw_timer_clkdiv_t clkdiv, HardwareTimerMode mode> uint32_t Timer1Api<clkdiv, mode>::interval;
 
-template <hw_timer_clkdiv_t clkdiv = TIMER_CLKDIV_16, HardwareTimerMode mode = eHWT_NonMaskable>
-
 /**
  * @brief Hardware Timer class template with selectable divider and interrupt mode
  */
+template <hw_timer_clkdiv_t clkdiv = TIMER_CLKDIV_16, HardwareTimerMode mode = eHWT_NonMaskable>
 using HardwareTimer1 = CallbackTimer<Timer1Api<clkdiv, mode>>;
 
 /**
diff --git a/tests/HostTests/modules/Clocks.cpp b/tests/HostTests/modules/Clocks.cpp
index 99163d6433..0c3cb62f08 100644
--- a/tests/HostTests/modules/Clocks.cpp
+++ b/tests/HostTests/modules/Clocks.cpp
@@ -31,7 +31,11 @@ template <class Clock, typename TimeType> class ClockTestTemplate : public TestG
 
 		printLimits();
 
-		for(unsigned i = 0; i < 2000; ++i) {
+		unsigned loopCount{2000};
+#ifdef ARCH_HOST
+		loopCount = 50;
+#endif
+		while(loopCount--) {
 			auto value = os_random();
 			check<NanoTime::Milliseconds>(value);
 			check<NanoTime::Microseconds>(value);
@@ -42,19 +46,39 @@ template <class Clock, typename TimeType> class ClockTestTemplate : public TestG
 
 		TEST_CASE("vs. system time")
 		{
-			constexpr uint32_t duration{2000000};
+			// Determine whether this is an up or down-counter
 			auto startTicks = Clock::ticks();
+			os_delay_us(100);
+			auto endTicks = Clock::ticks();
+			bool isDownCounter = (endTicks < startTicks);
+			debug_w("%s is %s counter", Clock::typeName(), isDownCounter ? "DOWN" : "UP");
+
+			// Run for a second or two and check timer ticks correspond approximately with system clock
+			constexpr uint64_t maxDuration = Clock::maxTicks().template as<NanoTime::Microseconds>() - 5000ULL;
+			constexpr uint32_t duration = std::min(2000000ULL, maxDuration);
 			auto startTime = system_get_time();
+			startTicks = Clock::ticks();
 			uint32_t time;
-			while((time = system_get_time()) < startTime + duration) {
+			while((time = system_get_time()) - startTime < duration) {
 				//
 			}
-			auto endTicks = Clock::ticks();
+			endTicks = Clock::ticks();
+			if(isDownCounter) {
+				std::swap(startTicks, endTicks);
+			}
+			uint32_t elapsedTicks = (endTicks - startTicks) % (Clock::maxTicks() + 1);
 
 			debug_w("System time elapsed: %u", time - startTime);
-			debug_w("%s ticks: %u", Clock::typeName(), endTicks - startTicks);
-			debug_w("Ratio: x %f", float(endTicks - startTicks) / (time - startTime));
-			debug_w("Apparent time: %u", uint32_t(Micros::ticksToTime(endTicks - startTicks)));
+			debug_w("Ticks: %u (%u - %u)", elapsedTicks, startTicks, endTicks);
+			debug_w("Ratio: x %f", float(elapsedTicks) / (time - startTime));
+			uint32_t us = Micros::ticksToTime(elapsedTicks);
+			debug_w("Apparent time: %u", us);
+#ifndef ARCH_HOST
+			// Up-timers may report 0 if inactive
+			if(endTicks != 0 || startTicks != 0) {
+				REQUIRE(abs(int(us - duration)) < 500); // Allow some latitude
+			}
+#endif
 		}
 	}