Hi,
found this router with interesting specifications that should support OpenWrt as per manufacturer but didn't find any official support here: https://downloads.openwrt.org/releases/23.05.2/targets/ramips/mt76x8/
It uses MT7628NN has 128MB of RAM and 16MB of NOR flash. Both 4G modems are seen as USB devices. Also has POE support.
The product page is here: https://m.zbtlink.com/sale-35970489d-dual-sim-4g-lte-outdoor-cpe.html
It costs $25/pc with minimum 2pcs per order...very affordable.
It appears that no LTE modem(s) are included in the base model. It has antennas, SIM slots, and space for customer's choice of modem.
Did found it also at AliExpress with double modems:
https://a.aliexpress.com/_Ex0p4iD and seems it has these modem chips, Quectel EC200A-EU, that are seen as usb devices (https://python.quectel.com/en/products/ec200a-eu -https://satronel.com/products/wireless-modules/4g-modules-en/iotm2m-optimized-lte-cat-4-module-quectel-ec200a-series-mini-pcie.html)
And a russian forum that discusses on it:
I got this router . Opening it, it shows a pretty decent build quality. Mine came with firmware V23.04.03.
LTE speeds seem a little slow, but I wonder if that is because the modem used in mine is a Quectel EC200A-EU, which is listed as "optimized for M2M and IoT. So probably not optimized for speed.
It does have 2 diversity antenna's, both going to the external ones, with the WiFi antenna's on the board itself.
I did manage to download an OpenWRT build from the manufacteerer, but did not try it. I guess that would be handy if I swapped the modem, so I could select all of the ones in OpenWRT repository.
-- edit --
Yeah, after putting it to some stress, indeed when I download a large 1GB image file from work, the modem heats up and resets, breaking the download. Never got further then 5 minutes/5% or so.
I think the base device is OK, pages respond well, no CPU speed problems. Though it has only WiFi 4, but I knew that, I always considered WiFi as the backup management interface, planning to use Ethernet cable.
ZBT sells it bulk without modem, but then resellers add modems at will. And mine came with the cheapest. (I now interpret "optimized for M2M" instead as "the cheapest we can make, because machines only send a few log and remote control bytes".
I guess if I want to make this work, I should get a better modem mini-pcix card. Or buy a proper ZTE or Huawei device.
Zyxel NR7101.
Well, I got modern OpenWRT v23 running on it: https://openwrt.org/toh/zbtlink/cpe2801