Blinking blue light off death

Hello there! I’m using an old dl2100, serial number is WDBBAZ0040JBK-20

I guess it’s a Gen. 3 device, since Gen.2 ends with xxx-10
And I’m pretty sure I’m at OS5.

I tried rebooting, resetting with both methods (4 and 40sec) but the device is not responding. Blue per button is blinking in a 1 sec interval, but I can’t access it by any means. Neither my windows pc or my fritzbox router list the nas device. So I was thinking:

Is there a way to force install OS5 via USB Stick?
Is there a recovery?
or is it even possible to install another Linux on it?

Best regards, awaiting a few good hints.

The Intel Attom CPU has probably died.

Is there any way to verify it? This nas hasn’t earned it’s money yet and it’s like to repair instead of investing into a new device.

Repair is not possible.