Hi Tinman,
something need to be test step by step:
1. check if the camera save setting after setup (setup in menu, quit menu, then enter menu, check the setting you just changed) ---- if this fail, means firmware problem;
2, check if the camera save setting after reboot (setup in menu, quit menu, manual power off, manual power on, enter menu, check the setting you just changed) ---- if this fail, means SPI flash problem;
3, check if the camera save setting after power cut off (setup in menu, quit menu, cut off power to power off, connect power to power on in seconds, enter menu, check the setting you just changed) ---- if this fail, means RTC battery problem;
4, check if the camera save setting after lont time off power (setup in menu, quit menu, cut off power to power off, wait for hours, connect power to power on, enter menu, check the setting you just changed) ---- if this fail, means RTC battery is not full charged;
hope this help to figure your problem out.