Yep, which is why you need to use a USB wall wart to supply power before turning on the controller. The controller does not supply power quickly enough to permit the monitor to setup and tell the controller the correct resolution. With power from the controller you will get default 680X480. There is enough power just not quick enough.
I have the same issue, and have tried all the suggestions above. Perviously when I had the issue, turning on the monitor prior to the controller solved it. However, now it will not. I have tried changing the “wall wart” usb power to the screen but nothing works. I am now using a USB mouse to navigate the elongated screen, and if I need to input a value (like bit diameter) I need to use a USB keyboard. Very disappointing.
the solution for this issue is to avoid auto-detection of the display resolution when powering on the CNC Controller, and instead to set the display resolution to the correct resolution of your display. This way you never have to worry to switch the display on before booting the CNC controller, because then the resolution will always be correct. See here for details.
Hey Aiph5u, Thank you!
Your solution of adding those lines to the configuration file worked perfectly.
It is always a pleasure to get a solution and an explanation from someone more knowledgeable than myself!