New UBports edition - black screen (backlight) only

[wibble]

Have you tried booting a known stable image like Jumpdrive from the SD to rule out the software as the cause? https://wiki.pine64.org/index.php?title=..._Jumpdrive

What you're describing reminds me of what some people have reported with UBports after an unclean shutdown - it gets stuck when trying to mount one of the filesystems.  They've fixed it by booting another OS on the SD to run fsck on the eMMC filesystems, or to reinstall UBports or another OS on the eMMC. If you want to find out what's actually going on behind the blank screen you can use the headphone socket as a serial console.

I flashed Jumpdrive to a microSD card using "dd if=pine64-pinephone.img of=/dev/sdc bs=1M", inserted the SD card and booted the Pinephone. I get a green LED, then the screen backlight lights up but no image on the screen.

Is it safe to say I have a bad screen and need to file a RMA request?

You've ruled out the most obvious software based problem, so it's probably a good time to contact them. The serial terminal would tell you more if you have the required hardware. Beyond that you'd have to open it up - some people have found incorrectly seated connectors, and solved problems by reseating them - so in your position I'd want to get the OK from Pine64 first. They may have some other things for you to check before RMA.