I’ve been using the mips_24kc-21.02.0 tag on https://hub.docker.com/r/openwrtorg/rootfs . However it appears to be a dead end at the moment as it looks like the mips kernel on the current release is not built with proper support for containers (http://forum.mikrotik.com/t/7-1rc3-containers-broken-on-mipsbe/151855/1)