I've been delayed from replying because new accounts can't post more than three replies to a topic 
Gave your firmware it a try but the problem is the same. I've filed a bug report - let's see if this is happening for anyone else.
Hi,
With the last firmware for EW1200, 2.4 Ghz works for me, but sometimes the SSID doesn't show. Need to restart to works fine.
Alas I've tried many restarts, both of the EW1200 and connecting devices.
I wonder if Afoundry might have quietly revised the chipset - I bought mine in July last year, how about yours? I may have access to a more recent EW1200 in a couple of weeks time so I'll try flashing LEDE on that to see if it's any different.
In fact you don't need an interface. I figured it out long after I sent my patch to LEDE, and I don't remember the exact details, but in essence:
In the stock firmware, use the configuration backup menu. You'll download a file.
I think the file is gzipped (not quite sure about that). If so, then gunzip it.
Then open it with a text editor (one that doesn't screw up the unix-style new-line sequence)
In there, you can find a line about a telnet server, which is set to false. Well, set it to true, and re-upload that config file to the router (gzip it again if necessary).
Well, now your router will give you a shell prompt when you telnet to it. Easy. No need to open the device 
I'm probaby too late for your case, but wanted to leave this comment in the thread for other people who may want to do this later on.
I've just updated to the latest ew1200-squashfs-sysupgrade.bin but it's still the same - no matter how many times I reboot, no 2.4Ghz network shows up on any of my devices. Is anyone else seeing the same problem?
Hi - I just got this router but have 2.4Ghz issues with latest OpenWRT. Is there a version of OpenWRT that works well with 2.4Ghz on this device?
PS: Can anyone post a working link to the stock firmware please or upload it?
Edit: got firmware already (thanks!), new link in case someone needs it
contains firmware 0.1.4 and 1.7.2
I tested various OpenWRT versions, from old to latest, 2.4G WIFI works very poorly in all of them (extremely low signal and very low transfer speed). In the stock firmware 1.7.2 the 2.4G WIFI works fine (full signal, 3x-5x faster transfer).
Further update - due to the poor signal with 2.4G Wifi for which I found no solution, I have created an image of OpenWrt 22.03.5 with the MTK proprietary driver (mt7603e) instead of the open-source mt76 driver that is shipped by default. It is based on https://github.com/Azexios/openwrt-r3p-mtk/tree/main but recompiled for the EW1200 device.
This solves the Wifi issues on this device.
You can download it here:
https://drive.google.com/drive/folders/1xzkwWrlDc70Nhudr-OjLpph0TC7XlGEQ?usp=sharing