TL-WR940N v6 (RU): Error code 18005

You flash the firmware for your model, the WR940N v6:

openwrt-18.06.0-ar71xx-tiny-tl-wr940n-v6-squashfs-factory
and
openwrt-18.06.0-ar71xx-tiny-tl-wr940n-v6-squashfs-factory-XX