Since this router has around 600 to 700 KBs of free space, running the hi link USB dongle modem should be done with the bare minimum packages
Here are the ones i installed to get mine running
opkg install kmod-usb-net kmod-usb-net-rndis kmod-usb-net-cdc-ether udev usb-modeswitch kmod-usb-serial-option kmod-usb-net
Right after, i rebooted, then running the command,
ifconfig -a
I got a new eithernet device (USB0), on another older hi link dongle it was called eth2.
Then, from within LUCI, you can simply add a new interface using this hardware interface, and set that to DHCP and add it to the WAN segment, You are done, it should be connected now
Please be aware that once you have it running, you might want to get into the dongle’s interface settings, and instruct the dongle to only use 3G (Not GSM/EDGE), i do that by visiting 192.168.8.1 (Hard coded, can not be changed, but depending on the model yours might be different).