Hello guys
I'm new to OpenWRT, trying it with my old router. Have flashed it and having:
OpenWrt 18.06.9 r8077-7cbbab7246 / LuCI openwrt-18.06 branch (git-20.319.49209-ab22243)
Easiest fix is to buy a new router https://openwrt.org/toh/views/toh_available_16128_ax-wifi
Your router is way past support, you can reset router to reset /overlay space, or use ancient imagebuilder to build image with changed wpad package. But it will not work well and have dozen security holes over internet and another dozen in wifi itself.
The free space in flash memory would be extremely limited, so yes, there is space, but not enough to install additional packages. Let's pretend you're on a flight that is usually completely booked... at the time of boarding, there are sometimes a few seats available, but that family of 6 who is flying standby is probably not going to fit.
Aside from that, it's possible you're looking at RAM, not flash storage. Your device has 4MB flash storage and 32MB RAM. They are different things and the RAM is not persistent storage, so you can't install packages there.
I'd ruther buy a new mikrotik. My old 941 can handle the newest 7.15.3 ROS. I thought openwrt is not a part of "marketing world" and gives you an oportunity to use any router.
OpenWrt supports hundreds of devices. However, very old devices are deprecated over time due to the lack of resources -- a 4/32 router cannot fit 19.07 and later. Much like how a very old Mac or PC cannot run the latest versions of MacOS or Windows.
Currently, 8/64 is required, but that will be changing with the next major release to 16/128. The increased resource demands come mostly from the upstream Linux kernel development.