How can I move a Wi-Fi driver from my Android phone to Linux Mint without internet?

If none of the USB methods work, another computer with internet access can download the correct Mint/Ubuntu Broadcom packages and all required dependencies onto a flash drive. A Linux-compatible USB Wi-Fi adapter is also an option, but choose one with in-kernel support; otherwise it may create the same offline-driver problem.

A manufacturer driver downloaded from Broadcom may not be the right thing to install directly. Mint normally uses its packaged Ubuntu-compatible Broadcom driver, and it may need matching packages, kernel headers, and build tools. Once you get any temporary internet connection, use Driver Manager or the package manager so dependencies are installed correctly.

USB tethering would be the easiest solution if the phone supports it. Connect with a confirmed data cable, then enable USB tethering in Android; Mint can often use the resulting network connection automatically. If the option stays disabled, the cable, phone policy, or carrier settings may be preventing it.

First check the simplest possibility: many USB-C cables are charge-only. Try a known-good data cable, unlock the phone before connecting it, and select “File Transfer” or “Android Auto” from the USB notification. If the phone is still absent from lsusb, try another cable or USB port. MTP should work without installing anything extra on Mint.

The flash drive may simply be formatted or partitioned in a way the phone no longer supports after creating the installer. If the data on it is not needed, recreate it as a single FAT32 partition, or use a different smaller flash drive and a USB-C OTG adapter. Since the laptop recognizes it, copying the file from the phone to that drive would work if the phone can mount it.