my method can be found at
then feel free to opkg update & install every remaining things on /etc/rc.local, as long as you have working network, and RAM is enough.
/etc/init.d is also stored in RAM, it wont survive reboot.
converting eth0 to dhcp client:
uci set network.lan.device=eth0 uci set network.lan.proto=dhcp uci set dhcp.lan=dhcp uci set dhcp.lan.ignore=1 uci set dhcp.lan.dhcpv4=disabled uci set dhcp.lan.dhcpv6=disabled uci set dhcp.lan.ra=disabled uci set dhcp.lan.ndp=disabled