TP Link Archer A7 tftp original firmware not flashing

I've been following this guide to restore the original firmware. I have successfully set up tftp and tried both the newest and oldest firmware listed here, but it's not being flashed.

If I watch the syslog, I see
May 30 15:34:04 local in.tftpd[17658]: RRQ from filename ArcherC7v5_tp_recovery.bin
so it seems that the bin is being downloaded when I turn the router on with the reset button pressed.

What else might I be doing wrong? Is there a specific firmware version I should be using? How could I tell?

I have the user and group of ArcherC7v5_tp_recovery.bin set to tftp.

Oh, and also now even though my openwrt defined wireless networks still exist and work, I can't log into the admin at