I have 3 RT-AC66uB1 routers set up as an Ai Mesh system, and wanted to post the only reliable technique I've found to get the nodes set up. I tried various techniques to set these up, using the web gui, smartphone apps, lan cables plugged in, not plugged in, etc. and this is the only way I've found to get it to work on these routers.
1. Decide if this is the best idea for your situation - will access points or a media bridge work for you? If so, do that
2. Separately update all routers to the latest firmware (stock is supposed to be the most reliable, but I've got it working fine with the Merlin firmware)
3. Set up the main router (first in line connected to the modem) in router mode, and set up your wifi / network settings the way you want it
Node Setup:
4. Power up the first node next to the main router with no patch cables attached
5. Use the Asus router app on iPhone or Android (I have only Android, but I'd assume this would work the same as iPhone) and login to your main router. Tap the "aiMesh WiFi System" icon on the bottom-middle of the screen, then tap Add Node
6. Tap Get Started and search for the node. Once it pops up, tap it to add.
7. Allow it to give you a message that it was unable to add the node, but don't tap Retry yet
8. Plug a patch cable from the main router LAN port into the WAN port of the node, then tap Retry. Select the node once it finds it and try it again
9. Let the setup finish, it takes a few minutes
10. Unplug the node and power up the next one, repeat node setup steps for each remaining node
11. Place your nodes where you want them and power them up!
1. Decide if this is the best idea for your situation - will access points or a media bridge work for you? If so, do that
2. Separately update all routers to the latest firmware (stock is supposed to be the most reliable, but I've got it working fine with the Merlin firmware)
3. Set up the main router (first in line connected to the modem) in router mode, and set up your wifi / network settings the way you want it
Node Setup:
4. Power up the first node next to the main router with no patch cables attached
5. Use the Asus router app on iPhone or Android (I have only Android, but I'd assume this would work the same as iPhone) and login to your main router. Tap the "aiMesh WiFi System" icon on the bottom-middle of the screen, then tap Add Node
6. Tap Get Started and search for the node. Once it pops up, tap it to add.
7. Allow it to give you a message that it was unable to add the node, but don't tap Retry yet
8. Plug a patch cable from the main router LAN port into the WAN port of the node, then tap Retry. Select the node once it finds it and try it again
9. Let the setup finish, it takes a few minutes
10. Unplug the node and power up the next one, repeat node setup steps for each remaining node
11. Place your nodes where you want them and power them up!