Rebooted, flashed with settings kept. No luci HTTPS when booted and password auth failed, but ssh worked with key auth.
Installed missing packages, rebooted and when booted there was no luci - HTTP or HTTPS. Login in with ssh, enabled and (re)started uhttpd and luci was back with working password auth.
Everything I've checked so far in addition to wired and wireless functions seems to be working fine: HE.net 6in4 tunnel, DDNS, USM drive with btrfs, minidlna, haproxy, ZNC.