Some devices only have a sysupgrade image, no factory image.
The dataentry says: LEDE Supported Current Rel: 17.01.3
Regarding the quality of the support: No clue. Until now, nobody bothered to write down installation instructions, and nobody confirmed that the image is really working: https://wiki.openwrt.org/toh/engenius/esr9850
I'm contemplating putting this on my 9850, but I was hoping someone else had already done it. I have the latest OEM firmware on it (2.1.3), but I'm looking to add the luci-app-sqm package. The QoS module in the OEM firmware is ok (I actually turn it off), but I want more "direct" control of the buffers.
If you do try it, please post back with your results!
I've all but given up on my 9850, which is EOL and receives no firmware updates (KRACK isn't and won't be patched, etc). If it works with an open source firmware, I may bring it back into service.
The thing I really like about it, even though it's ancient, is that it has gigabit ports on it! There's a lot of newer n/ac routers that don't, and aside from the buffer control, I really like my little box.
There's one mod I've made to it though - I've cut an opening in the top of the box and attached an 80mm fan which runs all the time. After burning through a number of routers, I've found this mod to be extremely valuable. =8o)
So after reading the 4/32 message on the website, I'm thinking I'm not going to do it. It's solid as it is, it's working, and I don't want to brick it. (I've bricked two Samsung laser printers if you can believe it.)