Tldr: I'm a noob and want to have 4g/LTE modem in a USB port of old router. Openwrt available for this model, but it's too big?
Buckle up for broken english too.
I'm trying to put said router to better use through updating it's capability to handle 3g/ 4g/Lte USB modem from it's current vampik firmware (DIR320-3.0.6.5218), but seeing openwrt flyer about 4/32 devices and size of latest 19.07.10 being above router flash size, I'm a bit at a loss what to do.
Does 19.07.10 even support USB modem?
Vampik sure does outta box, but lately try with modern "4g/LTE+wifi hotspot router" usb dongle didn't went fruitful, as asus sees it in usb port, but no surface messing with settings makes it cooperate (current old 3g ZTE dongle goes plug'n'play on 'ethernet over USB' setting in Wan), checked Dd-wrt - it doesn't, most simple USB support only, modems available from some mega-sized firmware, sure thing not fitting measly 4mb flash ram.
Nice to know, also I'm at rather low requirements for features - there is 2 cables goes in it LAN ports, one with camera and another with recording box for said camera, if another "4g-modem-wifi dongle" would work, router wifi pretty desirable to go as it seems to drop first under camera+wifi usage spike.
There is no other settings I did after quite few reflashes but "wan=ethernet from usb" & wifi ssid&pass. Well, admin pass obv.
Still, I've no clue about packages listed by download page, nor about how 4.5mb firmware expected to fit 4 (3.6?) flash ram.
Well, you need to have a look at compressed package size because packages get installed then compressed back into squashfs.
Your LTE dongle can fit in any router that has USB port. Nanopi or mikrotik hex if you dont need wifi functions (note 16/128 size and check that it certainly has USB-A port)