Yes, I know. This was like in ~2016 and even at that time you would need to build a custom image to fit OpenWRT in 4MB of Flash (I could fit LuCI and a few packages at the time, but I messed a lot with OpenWRT settings and every change I would have 1 in 4 chances of passing the 4MB limit and you would only discover this after building).

32MB is more reasonable, but even then I remember that it caused some issues with the bufferbloat scripts at the time, one of the reasons I went through the Gargoyle FW instead of vanilla OpenWRT.