This guide contains instructions to rotate an upside down touchscreen. If you received a BigTreeTech 4.3" touchscreen display, you will most likely need to follow these instructions:
Try to find config.txt from boot section and open it using your text editor of choice (i.e. Notepad++, VS code, VIM, etc.).
dtoverlay=vc4-fkms-v3d is found in config.txt, disable it by adding a hash (
#) at the beginning of the line:
The last step is to copy and paste the following content to the end of file:
After you are done, save and close the file.
Reinsert the SD card into your Raspberry Pi and reboot it.