Images for sd card
Same as you, I thought that my board was dead on arrival.
Here are few steps to bring android up:
-- USB-C power supply
I'm using a xiaomi PD unit, capable of delivering 15V/3A (45W), connect to port C0 next to HDMI port.
images are available from http://en.t-firefly.com/doc/download/51.html
I tried https://drive.google.com/open?id=1L-VcSFvAVxtalCeRfzPn_LgmPay6PvZ-
I confirm it works.
Just use dd to write the image directly to your sd card.
Insert the sd card into the slot above the black button (reset?) and power up the unit.
no google store available in this android image!
I'm still trying to sideload open gapps (https://opengapps.org/) but without success.
Also, I'm unable to boot android into recovery mode.
My 2 cents, hoping it will help some of you.
Please share your progresses.
at the bottom of http://wiki.t-firefly.com/en/ROC-RK3399-PC/started.html
"WARNING：The board is powered by PD (15V/3A, 45W), please use it with a suitable power supply."