My home network - OpenWRT on my "new" Archer c7 AC1750

I bought this explicitly to run OpenWRT, so the first thing to do is to get that installed.

• OpenWRT guide for TP link routers
• OpenWRT for TP Link C5 AC1200, C7 AC1750, TL-WDR7500

• OpenWRT downloads

openwrt-21.02.1-ath79-generic-tplink_archer-c7-v2-squashfs-factory-us.bin

We fool around a bit with ping and wireshark trying to figure out what IP address the router is set up on, but we give up on that and hold the reset button down on the back for 10 seconds to get to factory settings. We are warned it will appear as 192.168.0.1, so we disconnect ourselves from our local network (our router is already on 192.168.0.1).

After the reset it appears on 192.168.0.1. We use a browser to get its web interface and we login as admin/admin. Among the system tools is a "firmware update", we select that, choose factory.bin and away it goes. No need to fool around with putting the file on a tftp server or anything like that. When the update finishes, the web interface vanishes and it no longer pings at 192.168.0.1

The OpenWRT initial install page instructs me that it will appear on 192.168.1.1 and that I should login as root with no password.

I use the usual linux trick to put my desktop machine onto the proper subnet:

ip addr add 192.168.1.5/24 brd + dev eno1 label eno1:tplink

We configure SSID and passwords for the two radios (2.4 and 5 Ghz).
We set a root password.
We set a static IP on the "0.1" network that won't conflict with the existing router.

To disable DHCP, go to Network, LAN, Edit, DHCP server and click on "ignore interface".

Another one a year later

I use my main linux machine to do the upgrade. I need to disconnect it from the network (since the current router is on 192.168.0.1). This is how the game went:

Disconnect trona from network.
Connect new router to my local network switch.

Connect unit to power
Hold down reset button, turn on power,
continue holding 10 seconds.
Be patient after doing this, it will
appear as 192.168.0.1

Aim browser at it.  Get TP-Link page.
Login as admin/admin
Go to system tools -- firmware upgrade
Use "choose file"
select "factory.bin"
click "Upgrade" button
get progress bar for download, then restart.
The web page goes dead.
I reconnect via 192.168.1.1
Login as root with no password
Yay!  It is running Openwrt.

Wireless is disabled on both radios already
I go to System -- administration and set the root password
I go to Network -- Interfaces and change the static IP for LAN
I apply these, then reconnect the web page
to the new IP (192.168.0.1)

Now I check on DHCP.
Network -- Interfaces -- LAN
DHCP Server tab
Start 120 Limit 20 Lease time 12h
Save these settings.
Unplug the router and place in new location

Another one (April, 2023), this is an A7 version 5.8

• OpenWRT for Archer A7 v5

I power it up. It comes up as 192.168.0.1, but was asking for a password and admin did not work. So I did the deal of powering off, holding the reset while powering on, continuing to hold for 10 seconds, then waiting about a minute (I ran ping until I saw it respond). Then I could get the web page and go to advanced--system tools--firmware upgrade.

Here is was able to browse for the file. I just copied the archer-a7 file to /home/tom/factory.bin but I could have browsed to any file on my linux machine. Then we let the upgrade run its course which takes about 5 minutes perhaps. When it finishes the web page on 192.168.0.1 goes away and we need to see if it is responding on 192.168.1.1 as it should be. This requires the following old trick on my linux system:

su
ip addr add 192.168.1.11/24 brd + dev eno1 label eno1:bogus

I use System -- administration to set the root password.
I go to Network -- Interfaces and change the static IP for LAN to 192.168.0.53

At the top of the page we have "Qualcomm Atheros QCA9880 802.11acn, which must be the 5G radio. I click on "Add" and change the ESSID to "Agave". I attach this to the LAN network. My phone can now connect with no password.

Now I select WPA2-PSK and set the key to the usual thing. And it works! When I set the password in my phone I am connected.

Likewise, I set up the 2.4G radio, giving it ESSID of "Sotol". I set up WPA2-PSK in just the same way.

Interestingly, OpenWRT allows me to set up more than one SSID, so I set up both "Sotol" and the old "Coopers Hawk" on 2.4 Ghz -- this allows my ESP8266 weather monitor to continue communicating via Coopers Hawk. I also move both of these to channel 5 since nobody else in the neightborhood seems to be using that channel.

My pixel phone seems to automatically select "Agave", which is just what I want. Also the Wireless overview on the AC1750 shows me my pixel phone connected and gives me the MAC address and IP number, which is very nice. It shows 650 Mbit/s.