Sorry, forgot that you don’t have the internet working.
In that case you’ll need to download the package from another computer and transfer it in Qubes with USB drive.
Download firmware-libertas_20210315-3_all.deb from any mirror here:
Debian -- Package Download Selection -- firmware-libertas_20210315-3_all.deb
Copy it on your USB flash.
Plug in this USB in Qubes PC.
Open a new disposable VM terminal or some untrusted qube terminal and attach the USB flash partition to this qube:
How to use USB devices | Qubes OS
Then mount the attached USB drive partition in your qube terminal:
sudo mount /dev/xvdi /mnt
Then transfer the downloaded firmware package from your USB drive to debian-11 template by running this command in disposable/untrusted qube terminal:
sudo qvm-copy /mnt/firmware-libertas_20210315-3_all.deb
After it’ll finish the transfer open debian-11 template terminal and copy the downloaded package to the apt cache directory:
sudo cp ~/QubesIncoming/<replace this text with the name of disposable/untrusted qube>/firmware-libertas_20210315-3_all.deb /var/cache/apt/archives/.
Then try to install firmware again:
sudo apt install firmware-libertas
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