When the software is running in normal patron mode, you can enter the Maintenance mode by touching the four corners of the screen in configured order. The default configuration is 1234 which means a ”U” shape: start by touching the top left corner first, then bottom left, then bottom right and last the top right corner. This should now enable the maintenance mode; if it doesn’t, please wait a few seconds before attempting again, so that the device will clear its internal buffer from the previous attempt.