WAV LINK WL-WN575A3 - no access after FLASH

the Image: https://downloads.openwrt.org/releases/18.06.1/targets/ramips/mt76x8/openwrt-18.06.1-ramips-mt76x8-wl-wn575a3-squashfs-sysupgrade.bin cp file as firmware.bin to tftp-dir

flashed with TFTP, see that the LAN Interface got IP via DHCP.
See in DHCP Log: Nov 16 22:03:49 localhost dhcpd[8477]: DHCPREQUEST for from 80:3f:5d:xx:xx:xx (OpenWrt) via eth0

Can ping the IP but no TCP-Port open.

How can I fix this ?