Help needed to recover a DS918+

[alex3025]

Hi,

Some days ago, my DS918+ never booted up successfully after a sudden reboot (blue light blinking endlessly and all other lights are off), with and without hard disks.

When I connect the power, the NAS starts blinking without pressing the power button and the fans are spinning (after a couple of seconds they slow down but still spins).
If I hold down the power button for 10 seconds during the flashing, the NAS shuts down and restarts as soon as I release the button.

I have tried to make a UART connection to the NAS but get no output via the console (pin 2 GND and pin 4 TX, 115200 baud rate).

The CPU seems to be turning on: when I touch its heatsink I can feel that's warm.

I tried replacing the backup battery (although the original battery was charged) and bought a new power supply.
I also tried putting the original Synology ram bank (4 GB, 1866 MHz) into an old PC and running a memory test with MemtestX86 and no errors were found.

Now, I have connected the internal DOM to a PC and I can browse its contents.
I've already took a image of it with `dd` and it completed successfully I think, so the DOM itself should be OK, maybe jut the flash content (partition1 + partition2) have gone bad.

Any advices?
I really don't want to throw away this unit.