Back story, feel free to skip, see tl;dr below.
I have been using ath9k htc sticks for the past few years and while they're pretty stable they do suffer from a weird issue where the connection stalls and the interface has to be restarted. This happens seemingly randomly but can be expedited by multi thread downloading files from fast servers (not torrents). I've even compiled the driver with debug enabled but the logs don't show anything happening when the connection goes dead. Everything seems to be working but it's not.
When it happens everything appears to be fine, even Wavemon showing its active but in reality its not. I got too many headaches from it and it happens despite off the driver or firmware or even distro used. I've used both x86 and arm systems to run simple NAT with it.
Even on Windows it happens. Yes, I did setup a RRAS/NAT Windows Server for my sanity and it also happened with Windows drivers. I have several sticks from different brands all with the same ath9k htc chip. They all have the same issue. So I gave up on getting a stable 24/7 STA/client mode connection with that. Which leads me to this post.
From searching and reading the forum it seems Mediatek is a good chipset to try next. I've also given p on Realtek, the drivers are too unstable and the ones that do work in regular x86/arm devices I can't get to work on my ipq40xx based router (Fritzbox 4040).
I've been scouring the web for Mediatek based cards but its such a mess. Sellers advertising MT76 chipsets but in the sae listing also say it has RTLxxxx chipset. I've gambled on a few and received Realtek only. I have quite a collection of Realtek based cards and none of them work reliable in OpenWrt in client mode.
My question is where do I buy a real Mediatek usb stick that works with the OpenWrt drivers? I have found only one on eBay UK and it costs 25 euro which is very steep. I'd love to know some other places where I can buy Mediatek based sticks. Ideally in Europe for a reasonable price. Please drop links to Amazon/etc.
I'm also open for other sticks, as long as they're stable and work well in client mode on the ipq40xx platform. I don't need 5ghz or AC speeds, just something reliable. I did try some old Ralink Alfa cards I have here but the performance was very bad. I got 3-5mbit max whereas with the ath9k htc and the few Realtek ones hat work in normal Linux get me 70-80mbit.
Thank you for reading and thank you for any suggestions you may have.
PS: I'm also open to compile Realtek drivers that work in Linux into OpenWrt but I couldn't manage to get it to work. Those drivers do not compile for ipq40xx because they need adjustments I'm too stupid to make.