Had the exact same problem and your solution fixed it.In my code i wrote something in the RTC backup register:HAL_PWR_EnableBkUpAccess();
HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR1, 0);
HAL_PWR_DisableBkUpAccess();If i uncommet HAL_PWR_DisableBkUpAccess(...
