I forgot to backup the system on the TF card attached by Devterm when i open the box.
I used sudo apt update && upgrade.but i met some systemd problems after system upgrade and now the system boot abnormally.with error msg like flwg:
systemd-journald: Assertion ‘clock_gettime(map_clock_id(clock_id), &ts) == 0’ failed at
…/src/basic/time-util.c:55, function now(). Aborting.
I tried to find the solution but failed. I would like to re-install the respbian. I wonder whether the system installed on the TF card is customized and Is it suitable to install the orignal Raspbian iso downloaded on the official website of rpi to DEVTERM.