I also tried (and failed) create cheap+ultimate router/nas combo.
My choice of hardware wasn't the luckiest one, but, it's working, after desoldering and changing crap original usb wifi module with this https://www.aliexpress.com/store/product/MT5572-WIFI-module-6-pin-WL-UM01EBS-5572-V1-0-27-17-7mm-USB2-0/704833_32530090751.html
using rt2800usb driver with latest rt2870.bin
The problem is, it's working good, until I found, my wifi connection (n300) run at exactly quarter speed, instead of about half, which I am getting with Archer C7 for example.
On archer, I got iperf on 20MHz channel about ~72Mbit/s, on 40MHz ~150Mbit/s.
On the usb RT5572 module i got ~30Mbit/s 20MHz and 70Mbit/s - 40MHz
I know, that USB wifi was not bright idea for router, just want to ask, if this is "normal" behaviour, or if there is something, I can do about it (some tuning?).
I was looking into change USB polling rate, but only solutions I found was for USB mices.