TL-WR840N reboot loop and no signal

I have a problem with my router TP Link TL-WR840N . When i upgrade this. (openwrt-19.07.7-ramips-mt76x8-tl-wr840n-v4-squashfs-sysupgrade.bin) this firmware my router all lights are keep blinking , on and off and it won't stop . I can't even connect wifi signal to pc . What can i do know ??? please help.

TFTP recovery