1 files changed, 19 insertions, 0 deletions
diff --git a/src/main.cpp b/src/main.cpp
index 3d70af49..109971bc 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -300,10 +300,29 @@ void nimble_port_ll_task_func(void* args) {
 }
 }
 
+void calibrate_lf_clock_rc(nrf_drv_clock_evt_type_t event) {
+  // 16 * 0.25s = 4s calibration cycle
+  // Not recursive, call is deferred via internal calibration timer
+  nrf_drv_clock_calibration_start(16, calibrate_lf_clock_rc);
+}
+
 int main(void) {
   logger.Init();
 
   nrf_drv_clock_init();
+  nrf_drv_clock_lfclk_request(NULL);
+
+  // When loading the firmware via the Wasp-OS reloader-factory, which uses the used internal LF RC oscillator,
+  // the LF clock has to be explicitly restarted because InfiniTime uses the external crystal oscillator if available.
+  // If the clock is not restarted, the Bluetooth timers fail to initialize.
+  nrfx_clock_lfclk_start();
+  while (!nrf_clock_lf_is_running()) {
+  }
+
+// The RC source for the LF clock has to be calibrated
+#if (CLOCK_CONFIG_LF_SRC == NRF_CLOCK_LFCLK_RC)
+  nrf_drv_clock_calibration_start(0, calibrate_lf_clock_rc);
+#endif
 
   // Unblock i2c?
   nrf_gpio_cfg(Pinetime::PinMap::TwiScl,