Missing firmware

If you have the missing firmware warnings similar to below, you can try this.

update-initramfs: Generating /boot/initrd.img-6.9.7+bpo-amd64
W: Possible missing firmware /lib/firmware/rtl_nic/rtl8126a-2.fw for module r8169
W: Possible missing firmware /lib/firmware/i915/mtl_gsc_1.bin for module i915
W: Possible missing firmware /lib/firmware/i915/dg2_huc_gsc.bin for module i915
W: Possible missing firmware /lib/firmware/i915/mtl_huc_gsc.bin for module i915
W: Possible missing firmware /lib/firmware/i915/mtl_guc_70.bin for module i915

1) Get firmware files from git repository

git clone https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git   --depth=1

or alternative, only required files from 

https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/

2)  copy the files download in (1) to corresponding path, e.g.

rtl8126a-2.fw => /lib/firmware/rtl_nic/

 mtl_gsc_1.bin => /lib/firmware/i915/

3) Run update-initramfs  -u again.  Warnings should be gone this time.