Ubuntu is based on Debian, but it differs in quite a lot of ways.
Probably, they didn’t use dkms to install their custom wifi driver. If that was the case, Debian and Ubuntu behave identically and the driver isn’t added if a newer updated kernel is installed.
Especially if you use Ubuntu’s 6-monthly releases.
If their driver was included in a user PPA, it’s gone after a Ubuntu release upgrade and the sources.list of the PPA is deleted.
I may be wrong in that point.
However, the point I wanted to make is; all third party packages are uninstalled so reinstalling them without internet connection is quite challenging.
Probably, they didn’t use dkms to install their custom wifi driver. If that was the case, Debian and Ubuntu behave identically and the driver isn’t added if a newer updated kernel is installed.
If their driver was included in a user PPA, it’s gone after a Ubuntu release upgrade and the sources.list of the PPA is deleted.
IME PPA-sources.lists get disabled, not deleted.
I may be wrong in that point.
However, the point I wanted to make is; all third party packages are uninstalled so reinstalling them without internet connection is quite challenging.