Q4
A: You need to use the command: sudo apt-mark hold the raspberrypi-kernel ( lock the core to be unchanged)
Then use the command below.
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade (do not recommend this one, the update is the latest, but not safe)
If you do not do that above, the reboot will be failed.
When it occurs the situation that the screen touch is reverse, please go the official Raspberry Pi site to download the latest Raspbian OS, then use the DRIVER 0315 in our files.