[SOLVED] Confusing myself: router as an access point

It is really embarrassing to be so stupid:

My setup is as follows:
Gateway router connected to the internet is Asus RT-N66U with Tomato-Shibby MIPSR2-128 K26 USB AIO-64K located on first floor. IP is 192.168.1.1. Connected devices include 2 PCs by ethernet and an HP6600 all-in-one connected by wireless (only option) located on second floor and the secondary router connected by ethernet.
Secondary router is RT-N56U with factory (Asuswrt) firmware...

[SOLVED] Confusing myself: router as an access point