diff --git a/docs/radio_profiles.md b/docs/radio_profiles.md
index 68d22c369..071a2c0ac 100644
--- a/docs/radio_profiles.md
+++ b/docs/radio_profiles.md
@@ -339,8 +339,9 @@ receiver's setting does not lengthen packets sent by other nodes.
 `get radio2.timing` (alias `get radio.timing`) reports the active pair in
 `radio,radio2` order: dwell in chirps, recommended preambles in symbols, and
 the switching/loop allowances. Before calibration it reports `timing self-test
-pending` and the provisional preambles. On the T1000-E, the Full Companion now
-uses RTC2 for both retune timing and scan visits (about 31 us resolution).
+pending` and the provisional preambles. On nRF52 boards, enabling `radio2`
+uses RTC2 for both retune timing and scan visits (about 31 us resolution);
+turning `radio2` off stops RTC2 and returns to the usual `micros()` clock.
 Previously, the nRF52 `micros()` fallback counted 1,024 Hz RTOS ticks: a real
 sub-millisecond retune could be reported as exactly 977 us, and two ticks as
 1,953 us. Those old numbers are timer artifacts, not measured RF costs.
diff --git a/src/helpers/radiolib/RadioLibWrappers.cpp b/src/helpers/radiolib/RadioLibWrappers.cpp
index b4858665e..1de223ce1 100644
--- a/src/helpers/radiolib/RadioLibWrappers.cpp
+++ b/src/helpers/radiolib/RadioLibWrappers.cpp
@@ -24,32 +24,44 @@ static volatile uint8_t state = STATE_IDLE;
 // The Adafruit nRF52 core's micros() falls back to 1024 Hz RTOS ticks when
 // DWT is disabled. A sub-millisecond retune then appears to take exactly
 // 977 us (or 1953 us across two ticks), making the learned switch allowance
-// and scan dwell inaccurate. RTC2 is otherwise unused on the T1000-E and
-// provides a continuous 32768 Hz clock without changing micros() globally or
-// holding the high-frequency clock on for this measurement.
-static uint32_t profileTimestamp() {
-#if defined(T1000_E) && defined(NRF52_PLATFORM)
-  static bool started = false;
-  if (!started) {
+// and scan dwell inaccurate. On nRF52, RTC2 provides a 32768 Hz profile clock
+// without changing micros() globally or holding the high-frequency clock on.
+// Keep it stopped in the ordinary single-profile mode.
+static void syncProfileClock(bool dual_profile) {
+#if defined(NRF52_PLATFORM)
+  static bool active = false;
+  if (active == dual_profile) return;
+  if (dual_profile) {
     NRF_RTC2->TASKS_STOP = 1;
     NRF_RTC2->PRESCALER = 0;
     NRF_RTC2->TASKS_CLEAR = 1;
     NRF_RTC2->TASKS_START = 1;
-    started = true;
+  } else {
+    NRF_RTC2->TASKS_STOP = 1;
   }
-  return NRF_RTC2->COUNTER;
+  active = dual_profile;
 #else
-  return micros();
+  (void) dual_profile;
 #endif
 }
 
-static uint32_t profileElapsedUs(uint32_t since, uint32_t now) {
-#if defined(T1000_E) && defined(NRF52_PLATFORM)
+static uint32_t profileTimestamp(bool dual_profile) {
+  syncProfileClock(dual_profile);
+#if defined(NRF52_PLATFORM)
+  if (dual_profile) return NRF_RTC2->COUNTER;
+#endif
+  return micros();
+}
+
+static uint32_t profileElapsedUs(uint32_t since, uint32_t now, bool dual_profile) {
+#if defined(NRF52_PLATFORM)
+  if (!dual_profile) return now - since;
   // RTC2 is 24-bit and wraps every 512 seconds. Active scanning samples it
   // many times per second; a freshly configured profile gets a new visit stamp.
   const uint32_t ticks = (now - since) & 0x00ffffffUL;
   return static_cast<uint32_t>((uint64_t(ticks) * 15625 + 511) >> 9);
 #else
+  (void) dual_profile;
   return now - since;
 #endif
 }
@@ -66,7 +78,7 @@ void setFlag(void) {
 }
 
 void RadioLibWrapper::begin() {
-  (void) profileTimestamp();
+  syncProfileClock(_profiles.enabled());
 #ifdef USE_CC310_HW_CRYPTO
   // Initialize CryptoCell once from normal task context. The session helper
   // still initializes lazily if an earlier crypto operation runs first.
@@ -288,7 +300,7 @@ mesh::RadioParamApplyResult RadioLibWrapper::trySetParams(float freq, float bw,
     }
   }
 
-  _profile_visit_stamp = profileTimestamp();
+  _profile_visit_stamp = profileTimestamp(_profiles.enabled());
   return success ? mesh::RadioParamApplyResult::APPLIED : mesh::RadioParamApplyResult::FAILED;
 }
 
@@ -321,7 +333,8 @@ mesh::RadioParamApplyResult RadioLibWrapper::tuneProfile(uint8_t profile) {
   if (!_profile_refresh_required && _active_profile == profile && _profile_generation == _profiles.generation[profile]
       && _physical_preamble == preamble) return mesh::RadioParamApplyResult::APPLIED;
   if (!validateProfile(p)) return mesh::RadioParamApplyResult::FAILED;
-  const uint32_t started = profileTimestamp();
+  const bool dual_profile = _profiles.enabled();
+  const uint32_t started = profileTimestamp(dual_profile);
   beginProfileRetune(isInRecvMode() && !_rx_ps_armed && !_rx_ps_enabled);
   const uint8_t resume = beginReconfigure();
   if (resume > 1) {
@@ -364,13 +377,13 @@ mesh::RadioParamApplyResult RadioLibWrapper::tuneProfile(uint8_t profile) {
     if (restored) endReconfigure(resume);
     if (!restored || (resume && !isInRecvMode())) _profile_refresh_required = true;
   }
-  _profile_visit_stamp = profileTimestamp();
+  _profile_visit_stamp = profileTimestamp(dual_profile);
   // A profile retune re-enters RX on a different tuple. Do not read its
   // instantaneous RSSI until the chip family's settle interval has elapsed.
   if (applied && _nf_refresh_requested) {
     _nf_sample_from = millis() + NF_CALIB_SETTLE_MS;
   }
-  const uint32_t elapsed = profileElapsedUs(started, _profile_visit_stamp);
+  const uint32_t elapsed = profileElapsedUs(started, _profile_visit_stamp, dual_profile);
   if (elapsed > _profiles.longest_switch_us) _profiles.longest_switch_us = elapsed;
   // Require four good RX-to-RX hops in each direction before using the budget,
   // then continue raising the observed maximum as later good hops run.
@@ -403,6 +416,7 @@ mesh::RadioParamApplyResult RadioLibWrapper::tryRestoreCodingRate(uint8_t cr) {
 }
 
 void RadioLibWrapper::serviceProfileScan() {
+  syncProfileClock(_profiles.enabled());
   if (_cw_active) return;
   if (!_params_valid || (_profile_retry_at && (int32_t)(millis() - _profile_retry_at) < 0)) return;
   _profile_retry_at = 0;
@@ -477,13 +491,13 @@ void RadioLibWrapper::serviceProfileScan() {
         && visit_us < NF_CALIB_SETTLE_MS * 1000UL) {
       visit_us = NF_CALIB_SETTLE_MS * 1000UL;
     }
-    if (profileElapsedUs(_profile_visit_stamp, profileTimestamp()) >= visit_us) target ^= 1;
+    if (profileElapsedUs(_profile_visit_stamp, profileTimestamp(true), true) >= visit_us) target ^= 1;
   }
   const auto result = tuneProfile(target);
   if (restart_scan && result == mesh::RadioParamApplyResult::APPLIED) {
     _profile_scan_generation[0] = _profiles.generation[0];
     _profile_scan_generation[1] = _profiles.generation[1];
-    _profile_visit_stamp = profileTimestamp();
+    _profile_visit_stamp = profileTimestamp(true);
   }
   if (result == mesh::RadioParamApplyResult::FAILED) {
     // Retry a rejected or failing profile at a bounded rate; retain primary RX.
@@ -935,6 +949,7 @@ bool RadioLibWrapper::serviceCarrierWave() {
 }
 
 void RadioLibWrapper::loop() {
+  syncProfileClock(_profiles.enabled());
   if (serviceCarrierWave()) return;
   if (_profiles.enabled()) {
     const unsigned long now = millis();
@@ -1081,7 +1096,7 @@ void RadioLibWrapper::startRecv() {
   int err = startReceiveMode();
   if (err == RADIOLIB_ERR_NONE) {
     // A very short frame may complete while startReceiveMode() returns.
-    _profile_visit_stamp = profileTimestamp();
+    _profile_visit_stamp = profileTimestamp(_profiles.enabled());
     // Retain that RX interrupt instead of overwriting it with software state.
     noInterrupts();
     state = (state & STATE_INT_READY) | STATE_RX;
diff --git a/test/test_radio_profile_clock.py b/test/test_radio_profile_clock.py
new file mode 100644
index 000000000..f0eed6101
--- /dev/null
+++ b/test/test_radio_profile_clock.py
@@ -0,0 +1,74 @@
+"""Exercise the production profile clock on and off both nRF52 and other boards."""
+from pathlib import Path
+import os
+import subprocess
+import tempfile
+import unittest
+
+
+ROOT = Path(__file__).resolve().parents[1]
+SOURCE = (ROOT / "src/helpers/radiolib/RadioLibWrappers.cpp").read_text()
+CLOCK = "static void syncProfileClock(bool dual_profile) {" + SOURCE.split(
+    "static void syncProfileClock(bool dual_profile) {", 1
+)[1].split("// this function is called", 1)[0]
+
+HARNESS = r'''
+#include <cassert>
+#include <cstdint>
+struct FakeRtc {
+  uint32_t TASKS_STOP = 0, PRESCALER = 9, TASKS_CLEAR = 0, TASKS_START = 0;
+  uint32_t COUNTER = 0;
+} rtc;
+#define NRF_RTC2 (&rtc)
+uint32_t micros() { return 1234; }
+@CLOCK@
+int main() {
+  assert(profileTimestamp(false) == 1234);
+  assert(rtc.TASKS_START == 0 && rtc.TASKS_STOP == 0);
+  assert(profileElapsedUs(12, 42, false) == 30);
+#if defined(NRF52_PLATFORM)
+  rtc.COUNTER = 100;
+  assert(profileTimestamp(true) == 100);
+  assert(rtc.TASKS_STOP == 1 && rtc.PRESCALER == 0);
+  assert(rtc.TASKS_CLEAR == 1 && rtc.TASKS_START == 1);
+  rtc.TASKS_CLEAR = rtc.TASKS_START = rtc.TASKS_STOP = 0;
+  assert(profileTimestamp(true) == 100);
+  assert(rtc.TASKS_CLEAR == 0 && rtc.TASKS_START == 0 && rtc.TASKS_STOP == 0);
+  assert(profileElapsedUs(0, 32768, true) == 1000000);
+  assert(profileElapsedUs(0x00fffff0, 0x10, true) == 977);
+  syncProfileClock(false);
+  assert(rtc.TASKS_STOP == 1 && profileTimestamp(false) == 1234);
+  rtc.TASKS_CLEAR = rtc.TASKS_START = rtc.TASKS_STOP = 0;
+  syncProfileClock(false);
+  assert(rtc.TASKS_CLEAR == 0 && rtc.TASKS_START == 0 && rtc.TASKS_STOP == 0);
+  rtc.COUNTER = 200;
+  assert(profileTimestamp(true) == 200);
+  assert(rtc.TASKS_CLEAR == 1 && rtc.TASKS_START == 1);
+#else
+  assert(profileTimestamp(true) == 1234);
+  assert(profileElapsedUs(12, 42, true) == 30);
+  assert(rtc.TASKS_START == 0 && rtc.TASKS_STOP == 0);
+#endif
+}
+'''
+
+
+class ProfileClockTest(unittest.TestCase):
+    def test_clock_selection_and_lifecycle(self):
+        with tempfile.TemporaryDirectory() as folder:
+            cpp = Path(folder) / "test.cpp"
+            exe = Path(folder) / "test.exe"
+            cpp.write_text(HARNESS.replace("@CLOCK@", CLOCK))
+            for defines in ([], ["-DNRF52_PLATFORM=1"]):
+                result = subprocess.run(
+                    [os.environ.get("CXX", "g++"), "-std=c++17", "-Wall", "-Wextra",
+                     "-Werror", *defines, str(cpp), "-o", str(exe)],
+                    capture_output=True, text=True,
+                )
+                self.assertEqual(result.returncode, 0, result.stderr)
+                result = subprocess.run([str(exe)], capture_output=True, text=True)
+                self.assertEqual(result.returncode, 0, result.stderr)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/test/test_radio_profile_scan.py b/test/test_radio_profile_scan.py
index 3aec970b1..116ff5811 100644
--- a/test/test_radio_profile_scan.py
+++ b/test/test_radio_profile_scan.py
@@ -24,8 +24,10 @@ namespace mesh { enum class RadioParamApplyResult { APPLIED, BUSY, FAILED }; }
 static uint64_t elapsed_us;
 static uint8_t state;
 uint32_t micros() { return (uint32_t)elapsed_us; }
-uint32_t profileTimestamp() { return micros(); }
-uint32_t profileElapsedUs(uint32_t since, uint32_t now) { return now - since; }
+static bool profile_clock_active=false;
+void syncProfileClock(bool dual_profile) { profile_clock_active=dual_profile; }
+uint32_t profileTimestamp(bool) { return micros(); }
+uint32_t profileElapsedUs(uint32_t since, uint32_t now, bool) { return now - since; }
 uint32_t millis() { return (uint32_t)(elapsed_us / 1000); }
 struct Chip { bool standbyXOSC=false; int standby() { return 0; } };
 using CustomSX1262 = Chip;
@@ -59,7 +61,7 @@ struct RadioLibWrapper {
     state=STATE_RX; elapsed_us=100000;
     auto& p=_profiles.primary;
     p.freq=_cur_freq; p.bw=_cur_bw; p.sf=_cur_sf; p.cr=_cur_cr;
-    _profile_visit_stamp=profileTimestamp();
+    _profile_visit_stamp=profileTimestamp(_profiles.enabled());
   }
   bool isChipBusy() { return busy; }
   bool isInRecvMode() const { return (state & ~STATE_INT_READY) == STATE_RX; }
@@ -71,7 +73,7 @@ struct RadioLibWrapper {
   void startRecv() {
     if (failRxStarts) { --failRxStarts; state=STATE_IDLE; return; }
     if (_profile_rxps_suspended) assert(chip.standbyXOSC && !_rx_ps_enabled);
-    state=STATE_RX; _profile_visit_stamp=profileTimestamp(); _rx_ps_armed=_rx_ps_enabled;
+    state=STATE_RX; _profile_visit_stamp=profileTimestamp(_profiles.enabled()); _rx_ps_armed=_rx_ps_enabled;
   }
   void stopReceiveDutyCycle() { _rx_ps_armed=false; }
   bool applyParams(float f,float,uint8_t,uint8_t) { ++applies; elapsed_us+=switch_apply_us; return !fail || f==909.5f; }
@@ -100,6 +102,15 @@ struct RadioLibWrapper {
 @METHODS@
 int main() {
   using Result=mesh::RadioParamApplyResult;
+  {
+    RadioLibWrapper w;
+    w.enable();
+    assert(profile_clock_active);
+    w._cw_active=true;
+    w._profiles.setSecondary({},false);
+    w.serviceProfileScan();
+    assert(!profile_clock_active); // even a carrier-wave early return stops RTC2
+  }
   {
     RadioLibWrapper w; w.enable();
     assert(w._profiles.switchTestReady());
@@ -275,7 +286,7 @@ int main() {
     w.enable();
     w._floor_estimator.add(-100, millis());
     w._active_profile=0;
-    w._profile_visit_stamp=profileTimestamp();
+    w._profile_visit_stamp=profileTimestamp(w._profiles.enabled());
     const auto primary_visit=w._profiles.listenUs(0);
     elapsed_us += primary_visit - 1; w.serviceProfileScan(); assert(w._active_profile==0);
     elapsed_us++; w.serviceProfileScan(); assert(w._active_profile==1);