Swap the PCB board. Where is the firmware?

You need to be a bit more specific about your problem and your needs.

PCB burned some of the diodes (or how they are called) out. When I swap the PCB, I have to take the old firmware. Where is the PCB board firmware? Can I replace the diodes, or do I need to change the PCB?

You can start by replacing diodes, as copying the FW on those is not so easy as that.

Measure the TVS diodes and zero-ohm resistors. Use a digital multimeter set to the 200 ohms range. If the damage was restricted to these components, then you won't need a replacement PCB. A DIY repair should cost you nothing.

_________________
A backup a day keeps DR away.

TVS Diode next to the burnt area must be faulty.
Also check the resister marked 000 for open.
If open replace it

Two shows a zero-ohm 005, and the third did not show anything. TV diodes are also black (which is located next to the place burned)? Either do not show anything. Can the information which the diode to buy?
https://www.elfa.se/elfa3~ee_et/StartPage.do?ignorecookie=true

Be more specific or mark them and upload the image which one shows zero and which one doesn't

red- not show
black- show 005

If the "red" zero-ohm resistor is open circuit, then one would expect that the 12V TVS diode would be shorted.

I would remove the 12V diode (nearest the SDRAM chip), and bridge the resistor with a wire link between the adjacent cross-shaped pads. Better still, replace the diode with an SMBJ12A or equivalent, and add a 2A picofuse or smt fuse between the resistor pads.

_________________
A backup a day keeps DR away.