Ok, I just re-did the SD install of Android build #99 (Lollipop 5.1.1).
I did not flash the latest Android build #118—it failed when I did it the first time.
I see none of the LEDs come on when Android boots.
Note: it takes a little less than a minute for Qualcomm’s logo to appear, then it goes black, then about 2 minutes later, the Android screen pops up.
Then that will go back to black in a minute if there is no mouse/keyboard input—Android screensaver set to 1-minute timeout.
The blue LED only comes on when I turn on the Bluetooth–a steady blue, not blinking even when scanning for other BT devices.
You might want to try an SD card install of Android or Debian (at least it blinks a LED).
Or drop it into fastboot mode and see if you the fastboot tool “sees” something.
Just note: I ran into a problem when I re-used the uSD card I had used to do an SD image install of Debian. Even though I re-flashed it with an SD Android image, when I put it in the DB410C it said it was re-flashing Debian again. I did it twice, making sure I picked the right image and checking the write protect on my SD adapter carrier was off.
I eventually did a ‘dd if=/dev/zero of=/dev/mmcblk0 oflag=sync bs=1G count=8’ to zero it out.
Re-flashed SD Android image onto it again, that finally worked. Weird.