I installed debian jessie 2 months ago using an unofficial nonfree cd-image. With that my USB wifi stick worked flawlessly. I moved to version "stretch", I was unable to find nonfree version, and I cant make the OS to see any wifi networks. I added rtl_nic/rtl8168e-3.fw
to the bootdrive, becouse the installer said so. After that the installation went great (did not show to add that firmware) but still the wifi does not work.
Can you help me with that? How to install the TPlink 721n's driver? Thank you very much!