The wifi is kind of broken, at least in the HD3. It works if enabled in the PB system before starting KO. If the wifi is disabled when KO is started or we disable it manually within KO then it is impossible to enable it again.
I guess other devices are not affected and that's why @ezdiy didn't fix it yet. in fact it's in the to-do list in
https://github.com/koreader/koreader...ssue-688600676 as an improvement, not a bug fix.