Troubleshooting Airprint on HP m201dw

Just bought this printer, everything works well wirelessly except airprint from my iPad.

Hardware:

• HP m201dw printer, initially configured to a Windows 10 PC through USB to select wifi network, but now ruing wirelessly only on the main network on a dhcp-given ipv4. All default protocols enabled, including Airprint, Bonjour and IPP. Tried enabled IPPS, disabling ipv4, switching ePrint (web services), but nothing made a difference on airprint.
• Windows 10 PC coected to router on ethernet. Prints to the wireless printer just fine. No issues accessing printer config wirelessly using either HP toolbox or web browser on DCHP-given ip. Also, the Bonjour Browser utility can see printer services (screeenshot below).
• iPad Air ruing iOS 9.3.4. Caot see printer if coected on main wifi network. I can see and print using AirPrint when coected to the printer's own wifi network if "Wireless direct" is enabled on the printer, however that's not very useful - airprint is supposed to be available from the main wifi network on which all devices are coected.
• ASUS RT-N16 router ruing TomatoUSB firmware v1.28.9054. Tried enabling multicast and other options semi-randomly, to no avail.

Frankly, I don't really understand how AirPrint works and what it wants. After a couple of hours of troubleshooting, I'm now thinking Airprint require specific router support that I might not have. Any insights?