I have installed the 250 FW few years ago. Checked the setting-About, it shows 250. Never install any custom rom or twerp before. But I remember sometimes ago I have rooted I it with Kingroot and unroot it with Kingroot as well before uninstall it. I am not sure if the recovery partition already been overwritten. Is there any other way out? Sorry, I’m not good that this. Thanks a lot.