DS2413+ trying to find where the UART port is and looking for a bios

[BangFR]

Hi,

I'm trying to get a DS2413+ revived (blinking blue light, no beep), the power are good, the DOM is clean and seems healthy (6Mb/s)
The battery cell is ok (3v for CR2032)

So I suspect the bios but before desoldering the chip i was trying to listen to the boot thru the console and I could find where to plug my TTL adaptator
There is a COM port (DB9) at the back but I didn't get any information that it was the correct one, on the contrary it seems to be used to connect UPS.

So here is the photo of the board, i suspected JP1 because this is the only one with pin on it
JP2 on the upper left could be the one

Does anyone know how to connect the TTL to this model of NAS ?

Is anyone get a bios of this model ?

Thanks a lot for your help

 

[BangFR]

Found it there Connecting console reference guide

So it was the COM port, haven't tried yet but the document explain all for all models of synology how to connect console to get a log (and interact) with your NAS.
It's really usefull to identify the problem because most of the time you would get a clue on it...

Still looking for DS2413+ bios, thanks a lot