There's enough posts in all the threads about mt7621 in my original post to make me cautious though... it sounds like there is a fundamental issue with switching that just doesn't seem to quite get fixed with every stable release - just as one thing seems resolved, another rears its head. Anyone else have solid uptime from an mt7621 device?
To be fair, I also have a second mt7621 device running in a different environment which would reboot/lock-up once a week on average. This is presumably because it is connected to a switch which utilizes pause frames, and for some reason there is a bug with the mt7530 that causes it to misbehave with pause frames. I have written an experimental patch that disables pause frames completely and this Monday it will officially have 4 weeks of total stability.
So depending on your environment, your mileage may vary
For x86 you should be looking at de-commisioned Thin clients instead, usually fanless and have crappy specs for a PC but for OpenWrt it's plenty (512MB RAM or more is common, and plenty of internal flash space for OpenWrt). They are also more or less the same size of a router, or slightly bigger.
While older thin clients and Dell/Wyse clients are semi-custom affairs that need to be hacked to run something else that isn't their original firmware, HP thin clients from series 57xx onwards (and series 510 and 610 onwards, although the 510 use VIA CPUs and I hate VIA) are normal x86 PCs with a normal BIOS/UEFI and normal Sata/IDE interfaces, that can boot from USB as well.
You can find more info about thin clients on this site https://www.parkytowers.me.uk/thin/ but also by just googling with the product name, many people are repurposing them as mini-PCs nowadays, and HP provides extensive documentation with service manuals and whatnot.
Decommissioned thin clients are (and will be) available in large numbers so in many cases you can also get discounts for bulk purchases.
Usually the ones with Atom CPUs (and later) should have a mini pcie slot you can put a card in to create a wifi network, or have already one with wifi n. These cards are easy to get and cheap, 10 euro tops.
Cables and antennas if needed another 5 euros tops. Not all thin clients have a hole for an external antenna, but it's usually easy enough to drill a hole in the back plate if they don't.
Since most don't have 2 ethernet ports, you can add a USB-ethernet adapter using the ASIX chipsets (realtek chipsets aren't great on PCIe but in USB adapters they really are unstable garbage).
For example the Ugreen brand ones you find on ebay are relatively cheap (10 euro for a USB 3.0 gigabit adapter) and use an ASIX usb ethernet chipset. I use them and they actually hold under 100% load for days on end when I'm running large backup jobs over the network. (Realtek ones... don't. Not even the realtek ethernet of my laptop is stable enough, it will reset or even lock up after a few minutes if actually loaded like that)
Optimal would be to get a thin client that has USB 3.0, but they work fine on a 2.0 port as well (will be limited to 100-ish Mbit speeds of course).
So yeah it's still a clown-car-ish setup, so you should probably keep this as a fallback in case you don't find routers that satisfy your requirements, but even if you are going for the best specs without no bulk discount like I did above you won't spend more than 100 euro or 90 pounds apiece for a complete system, and also since it is still overkill for routing job it will last a very long time.
About mt76: https://github.com/openwrt/mt76/issues - just look how much open issues are there without responses, and how many commits are fixes for old mt76x2 and 7603 chipsets.
The same will eventually happen to mt7615 and finally to mt7915.
And about mt7621 - there is a patch for mt7530 which which fixes problem on some devices and introduces it on another.
@bobafetthotmail - thanks so much, that's a really comprehensive write-up. A lot of people on the Pfsense forums are really down on the use of USB>Ethernet adapters as if it's some kind of heresy, so it's good to hear the ASIX ones can take sustained load without falling over.
To be honest, even the single Realtek NIC on my Chromebox hasn't really had a hiccup either, but I see it as a bonus rather than the norm.
There are also ethernet cards available in mini-PCIe form factor, which is probably a better use for a single expansion port, than 'wasting' it on a single wireless card (this is cheaper/ easier to outsource to a simple OpenWrt AP).
I expect any thin client to come with one onboard ethernet card, if you have a mini-PCIe slot available, you can add another using this slot (yeah, you will have to do a little diy to fit the rj45 connector into the case). With two ethernet cards, WAN and LAN are covered, so you don't need to use VLANs for simple router uses, but you obviously can define as many VLANs as you like on the LAN (or WAN) interface and break them out to a managed switch.
And I agree with them. If you use Pfsense, OPNSense or FreeNAS/TrueNAS, stay away from USB adapters and from realtek cards. They are all derivatives of FreeBSD operating system so they act similar.
OpenWrt is different from them because it's a Linux system (Like ChromeOS, Ubuntu, Debian, RHEL, Fedora, OpenSUSE and others). Since Linux is much more popular than FreeBSD on PCs, laptops and embedded devices, the drivers for "non-server" hardware on Linux are usually much better.
Afaik the Realtek card driver for FreeBSD can crash randomly, drivers for some Realtek USB adapters don't exist at all, and the driver for ASIX USB-ethernet chipsets is subpar (cuts the bandwith down to 250Mbit last time I tried it, while on Linux it runs at nearly 1Gbit for days, as it should).
Well, I've received ER-X less than a month ago, but it's been pretty good. I've been replacing switches/outlets and switching off the main breaker panel every now and then, so it doesn't have a solid uptime, but it's been pretty reliable so far. Also, I've looked at the MT76xx issues @lukasz92 listed and looks like majority of them are for WiFi issues, hopefully I won't run into problems with the wired router.
I still have the same issues. If I use master, port isolation does not work. If I directly define interfaces with e.g. eth0.10, it works but then I test iperf, the direction from router to my client pc is max 10MBit/s. So everything is still the same. You have to revert the ip40xx edma changes.
Had to wait for a window to take down my X86 setup and replace with the EA6350 - results so far are good though! Easily handling 200/20 with cake and piece_of_cake and the WiFi seems about equal to the Unifi UAP-AC-Lite I have here. Looks like it's a good shot for the UK as I keep seeing people selling them for about £20-25 on eBay. I won't mark this as "solved" necessarily as some of the other options are also compelling.
EDIT - to clarify, I stuck with 19.07.3 and manually defined my VLANs by directly editing config files and all works well
EDIT 2 - Ah, 2.4Ghz drops off a cliff once you get too far away (2-3Mbps download and upload in a location that easily gets 30-40Mbps from the Unifi AP). There is some info about CT firmware in this thread:
Just need to clarify where exactly to get "pwr.bin" then I'll try it to see if it solves it. Not a biggie for me as I can use it without WiFi (I have the Unifi AP anyway) but obviously a deal breaker if attempting to use it as a combined router and AP...
Well, after replacing the firmware blob (the other thread is now updated, thanks @eginnc!) I got an improvement in 2.4Ghz performance, but it's still not as good as the UniFi AP (in the same spot, the EA6350v3 with replaced blob still only gets about 4Mbps up and down and the UniFi AP gets about 15Mbps). 5Ghz is pretty much the same for both of them.
But overall, an EA6350v3 second hand for about £20-25 seems to be a no brainer, especially as a wired-only device since it can happily shape my 200/20 connection.
I'm going to leave this thread unsolved in case anyone wants to add any devices to those mentioned above (but thanks to everyone who chipped in with suggestions - this thread is a a handy resource now).