To prevent upgrade failures you need to make sure that you are typing the correct hardware version while uploading firmware in the Tp-link range extender. Outdated firmware could void the warranty and may damage the product. Once you have downloaded the firmware, keep it in an accessible location, and do not forget to extract it. You can use the decompression software for extracting the firmware such as WinRAR, WinZip etc. The upload process will get initialized from the tplinkrepeater.net interface.
https://setup-tplinkrepeater.net