Had my 8000NEX installed this afternoon and cannot access the Disc button to open the screen. I've downloaded the 1.08 firmware update but cannot open the screen to insert the SD card. Anyone have any idea what the installers did wrong?

Not knowing what you have tried, I am going to try to help. To open, press the manual button on the right side that has the up arrow with a line underneath it. then the screen will show 4 options, insert disc on the left, then insert sdcard next, then tilt screen one way, then tilt screen another way. It is on page 15 of manual. 

Also, inputs will be greyed out, if there is nothing connected. If usb1 is greyed out, then there is nothing hooked up to it. Your unit has two usb inputs and installer should have routed the usb extensions to someplace in your vehicle where you could hook up something to them. 

Please post what you have tried and we can maybe deduct what issue there is.

Following your instructions I was able to open the the screen and complete the firmware update. On the Home screen both the 'Disc' and USB1 remain greyed out. I removed the head unit and do have an Apple Lightening cable inserted in the USB1 slot running to an Apple Digital Adaptor along with an HDMI cable.

Any chance Disc is not available because you don't have a disc inserted?

Any chance USB is not available because you don't actually have a usb device connected? (An adapter is not a device.)

Absolutely correect on the Disc. Put one in and it works great. I'm now gettin incompatible USB. Bought it from Apple. Is there more than one type of lightening cable?

If you have apple adapter hooked up to usb1, it is only going to charge the phone, and not receive any signal from it. New firmware may grey it out when it is hooked up to a/v adapter, wheres before, it would show error of "not a compatible device". You have to understand the apple a/v adapter, splits the audio/video and sends thru hdmi, and charges thru the lightning. If you are going to use the apple adapter, just run the lightning to usb cable to a car charger, and that leaves usb1 open for other use. You could get additional lightning cable and hook up to usb1, or if you want to use carplay, then leave lightning cable as it is and unplug it from the apple adapter and plug directly into phone, thereby making carplay available(just make sure and setup smartphone setting to usb and enabling carplay in settings), If you want to use iPhone in iPod mode just plug it in and disregard enabling carplay. I have experience with about everything you can hook up to these nex units.

Absolutely correect on the Disc. Put one in and it works great. I'm now gettin incompatible USB. Bought it from Apple. Is there more than one type of lightening cable?

This is what i was talking about in previous post, Incompatible usb. if you unplug it from the adapter and straight to the iPhone then usb1 will light up, for it is now in full connection mode with iPhone, not just sending electricity to charge phone.

Worked like a charm. Much thanks.