If the device does nothing else than a steady blue light and green on ether2 regardless of reset button holding before and after applying power, it is most likely dead. Hope it is still under warranty.
Well, AFAIK you cannot really say that Netinstall won't work unless you try It and actually It doesn't work.
Then It will be time for opening a support ticket with Mikrotik and/or your local distributor.
I have the same problem. I tried transferring the dump from the working 5009upr to mine, but it still freezes. I also tried using GitHub - kaechele/rb5009-unbrick: Unbrick your universally bricked RB5009 · GitHub , but to no avail. I have bad sectors in my NAND, could that be the reason? The most interesting thing is that the error seems to be related to ATF, since the custom bootloader works. I get a freeze (user+sfp+(eth2 always) light up after~ 5 sec boot). I have 5009upr. BB -7.8, fw/ros7.19.2.
Has anyone had experience replacing the NAND or SPI on the RB5009?