first install on most D-Link devices works with
- only factory image works
- only via D-Link emergency room boot sequence
there were reports about several dir-2660 variants, I once tried to summarize them in a post: D-Link DIR-2660 rev A1 Not Working After Successful Upgrade - #8 by Pico
My impression was that all 3 of the 2660 variants are supported with recent 22 releases?
Edit: Oh, but wait, there is more ;-), almost forgot, on top of it, you may have hit an unrelated issue: many D-Link devices with emergency room boot option have an incorrect http-100 implementation in the emergency room. Several http clients fail on that, as the client sends rfc-conform http-100, but the emergency room mini server does not respond properly, I think it might stall the client then.
I think trying different browsers, not on Linux, but on Windows (Chrome? Firefox?) or disabling 100 in the client was a viable workaround.