Bricked IB NAS 4220 B

Hi,
please help me, my NAS IB 4220 B is brick after installation open wrt firmware, device not working, not power on, only LED on RJ45. Please help me upload new firmware via serial port.
Thx.

since you have serial, post the output of the failing openwrt boot sequence.

How to show boot sequence? Via serial.
How Used software? I need windows or Linux? And software in the operating system?
I am beginner in serial communication. Please step by step. Thanks you.

putty on windows, screen, minicom etc on linux.

doesn't matter.

https://openwrt.org/docs/techref/hardware/port.serial
https://openwrt.org/docs/techref/hardware/port.serial.cables

Config parameters serial communication?
Speed, and other?

no idea, couldn't find anything, your google skills are probably as good as mine.

start with 115200,N81, no flow control.
if it doesn't work, reduce the speed, keep the rest.

keep in mind the serial 3.3v (?) pin shouldn't be connected to the PCB,
use only three wires.

Ok, connect only TX, RX, GND, and connect original power supply?

yes, NAS needs to be powered by it's own power adapter.

btw, what guide were you following when you installed openwrt ?

Ok and next?
Connect all 3 wires to usb rs232 and connect all 3 wires to IB NAS.
USB -> NAS

RXD -> 2
TXD -> 3
GND-> 5
OK?

And next connect power supply?
Or firstly run terminal software and next connect power supply?

connect wires
start serial app, and start monitoring the port
power on

if you get garbage, it's the wrong speed.
if you get nothing, swap the Rx and Tx wires.

How to start monitoring serial?

in Linux it's probably as soon as you set up the connection.
in Windows (putty) you need to click "Open".

After connect power supply to NAS the red led on USB-RS232( RXD and POWER) LED on. USB is connected to PC.
This is ok?

this is probably wrong, you'll need an USB TTL, or RS232 to TTL.

I used USB-TTL CP2102

where did RS232 come from ?

then you're probably good to go.

Sorry bad word.
The correct is USB-TTL CP 2102