w: possible missing firmware /lib/firmware/rtl_nic/rtl8125a-3.fw for module r8169

Whenever I try to install any drivers or something I get this error. Because this error I guess I am not able to on the machine. I have booted normal from recovery mode after that I have rebooted system but no luck.

w: possible missing firmware /lib/firmware/rtl_nic/rtl8125a-3.fw for module r8169 
w: possible missing firmware /lib/firmware/rtl_nic/rtl8168fp-3.fw for module r8169 
i: the initramfs will attempt to resume from /dev/nvme0n1p4 
i: (uuid=827a4ecd-a3d9-4990-8a01-bb7aa2a57a22) 
i: set the resume variable to override this.

There is a similar bug reported here : Debian Bugs

The files rtl8125a-3.fw and rtl8168fp-3.fw can be found on:

Git Kernel

Then run the commands :

sudo cp ~/Downloads/*.fw /lib/firmware/rtl_nic/
sudo update-initramfs -u

The issue looks like this one : Possible missing frmware /lib/firmware/i915

Got similar error message on system with MSI MPG B550 Gaming Edge WIFI motherboard and Realtek RTL8125 2.5Gbe onboard NIC and 5.10.21 kernel (FYI: needed 5.10 kernel for proper AMD 5800X CPU and RTL8125 support):

Possible missing firmware /lib/firmware/rtl_nic/rtl8125b-2.fw for module r8169

Solved it from your response - by downloading firmware files and including them into initramfs:

mkdir rtl8125b_fw
cd rtl8125b_fw
wget https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/plain/rtl_nic/rtl8125b-2.fw
wget https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/plain/rtl_nic/rtl8168fp-3.fw
sudo cp *.fw /lib/firmware/rtl_nic/
sudo update-initramfs -u

with reboot afterwards. Didn't seen missing firmware warning anymore.

Firmware for new Realtek Ethernet chipsets is missing in the linux-firmware package provided with the Ubuntu release.

It is very unlikely that you have one of these new chipsets, because your network is working.

So this warning is harmless and doesn't need any "fix".