According to the sticker I own a TPLink Archer A6 EU V2.0. It refuses any UI upgrade. I've set up the TFTP server, wireshark, enter in restore mode, router asks for ArcherC6v2_tp_recovery.bin, the server starts to push to 192.168.0.86 very fast reaches the last packet, all packets are acknowledged correctly. At this time the WPS led is off, the router boots up in ~30-40s to the original firmware. Tried with openwrt-21.02.1-ath79-generic-tplink_archer-c6-v2-us-squashfs-factory.bin also with generic/openwrt-21.02.0-ath79-generic-tplink_archer-c6-v2-squashfs-factory.bin.
Any help is greatly appreciated.