diff --git a/firmware/controllers/trigger/trigger_decoder.cpp b/firmware/controllers/trigger/trigger_decoder.cpp
index e50964b525..be614f2d6a 100644
--- a/firmware/controllers/trigger/trigger_decoder.cpp
+++ b/firmware/controllers/trigger/trigger_decoder.cpp
@@ -239,7 +239,7 @@ void PrimaryTriggerDecoder::resetInstantRpm() {
 void PrimaryTriggerDecoder::movePreSynchTimestamps() {
 	// here we take timestamps of events which happened prior to synchronization and place them
 	// at appropriate locations
-	auto triggerSize = getTriggerSize();
+	auto triggerSize = getTriggerCentral()->triggerShape.getLength();
 
 	int eventsToCopy = minI(spinningEventIndex, triggerSize);
 
@@ -283,8 +283,10 @@ float PrimaryTriggerDecoder::calculateInstantRpm(
 	if (time90ago == 0) {
 		return prevInstantRpmValue;
 	}
-	// we are OK to subtract 32 bit value from more precise 64 bit since the result would 32 bit which is
-	// OK for small time differences like this one
+
+	// It's OK to truncate from 64b to 32b, ARM with single precision FPU uses an expensive
+	// software function to convert 64b int -> float, while 32b int -> float is very cheap hardware conversion
+	// The difference is guaranteed to be short (it's 90 degrees of engine rotation!), so it won't overflow.
 	uint32_t time = nowNt - time90ago;
 	angle_t angleDiff = currentAngle - prevIndexAngle;
 
@@ -316,13 +318,18 @@ void PrimaryTriggerDecoder::setLastEventTimeForInstantRpm(efitick_t nowNt) {
 		return;
 	}
 	// here we remember tooth timestamps which happen prior to synchronization
-	if (spinningEventIndex >= PRE_SYNC_EVENTS) {
+	if (spinningEventIndex >= efi::size(spinningEvents)) {
 		// too many events while trying to find synchronization point
 		// todo: better implementation would be to shift here or use cyclic buffer so that we keep last
 		// 'PRE_SYNC_EVENTS' events
 		return;
 	}
-	spinningEvents[spinningEventIndex++] = nowNt;
+
+	spinningEvents[spinningEventIndex] = nowNt;
+
+	// If we are using only rising edges, we never write in to the odd-index slots that
+	// would be used by falling edges
+	spinningEventIndex += engineConfiguration->useOnlyRisingEdgeForTrigger ? 2 : 1;
 }
 
 void PrimaryTriggerDecoder::updateInstantRpm(
diff --git a/firmware/controllers/trigger/trigger_decoder.h b/firmware/controllers/trigger/trigger_decoder.h
index 9548e65582..4aeb554f4b 100644
--- a/firmware/controllers/trigger/trigger_decoder.h
+++ b/firmware/controllers/trigger/trigger_decoder.h
@@ -184,10 +184,6 @@ private:
 	Timer m_timeSinceDecodeError;
 };
 
-// we only need 90 degrees of events so /4 or maybe even /8 should work?
-#define PRE_SYNC_EVENTS (PWM_PHASE_MAX_COUNT / 4)
-
-
 /**
  * the reason for sub-class is simply to save RAM but not having statistics in the trigger initialization instance
  */
@@ -213,8 +209,10 @@ public:
 	uint32_t timeOfLastEvent[PWM_PHASE_MAX_COUNT];
 
 	int spinningEventIndex = 0;
+
+	// we might need up to one full trigger cycle of events - which on 60-2 means storage for ~120
 	// todo: change the implementation to reuse 'timeOfLastEvent'
-	uint32_t spinningEvents[PRE_SYNC_EVENTS];
+	uint32_t spinningEvents[120];
 	/**
 	 * instant RPM calculated at this trigger wheel tooth
 	 */
diff --git a/unit_tests/tests/trigger/test_fasterEngineSpinningUp.cpp b/unit_tests/tests/trigger/test_fasterEngineSpinningUp.cpp
index 0c9105c822..9b3539fc29 100644
--- a/unit_tests/tests/trigger/test_fasterEngineSpinningUp.cpp
+++ b/unit_tests/tests/trigger/test_fasterEngineSpinningUp.cpp
@@ -119,8 +119,34 @@ static void doTestFasterEngineSpinningUp60_2(int startUpDelayMs, int rpm1, int e
 	EXPECT_EQ(expectedRpm, round(Sensor::getOrZero(SensorType::Rpm))) << "test RPM: with " << std::to_string(startUpDelayMs) << " startUpDelayMs";
 }
 
+static void doTestFasterEngineSpinningUp60_2_onlyRise(int startUpDelayMs, int rpm1, int expectedRpm) {
+	EngineTestHelper eth(TEST_ENGINE);
+	// turn on FasterEngineSpinUp mode
+	engineConfiguration->isFasterEngineSpinUpEnabled = true;
+	engineConfiguration->useOnlyRisingEdgeForTrigger = true;
+
+	setupSimpleTestEngineWithMaf(&eth, IM_SEQUENTIAL, TT_TOOTHED_WHEEL_60_2);
+	eth.moveTimeForwardMs(startUpDelayMs);
+
+	// fire 30 tooth rise/fall signals
+	eth.fireTriggerEvents2(30 /* count */, 1 /*ms*/);
+	// now fire missed tooth rise/fall
+	eth.fireRise(5 /*ms*/);
+	EXPECT_EQ(rpm1, round(Sensor::getOrZero(SensorType::Rpm)));
+
+	eth.fireFall(1);
+	eth.fireTriggerEvents2(30, 1);
+
+	// After some more regular teeth, instant RPM is still correct
+	EXPECT_EQ(rpm1, round(Sensor::getOrZero(SensorType::Rpm)));
+}
+
 TEST(cranking, testFasterEngineSpinningUp60_2) {
 	doTestFasterEngineSpinningUp60_2(0, 1000, 1000);
 	doTestFasterEngineSpinningUp60_2(100, 1000, 1000);
 	doTestFasterEngineSpinningUp60_2(1000, 1000, 1000);
+
+	doTestFasterEngineSpinningUp60_2_onlyRise(0, 1000, 1000);
+	doTestFasterEngineSpinningUp60_2_onlyRise(100, 1000, 1000);
+	doTestFasterEngineSpinningUp60_2_onlyRise(1000, 1000, 1000);
 }