I have exactly the same problem with my non-eMMC X86J4105. The BIOS.nsh successfully wrote and verified the flash, but on the next start nothing happened for more than thirty minutes.
I have tried multiple times to remove power and battery. When I connect the PSU again, it starts immediately without pressing the power button, but does not initialize the HDMI or POST.
I am wondering what the cause could be? The flashing worked, so the BIOS should not be corrupted. What is it supposed to do in those 6-8 minutes on the first start after flashing and what could go wrong there?
Is there some way to revert to a functioning BIOS? Does the Winbond memory next to the NICs contain the BIOS? Would it be possible to flash it with an external programmer?
Since you did not buy from our website, and warranty from distributor is over, the only solution remaining would be to flash the BIOS chip. Can you find any local repair shop to help you with this? When you download the BIOS files, there is a file with a “.bin” extension. That is the file that needs to be flashed to the BIOS chip.