To restore configuration files, you can upload a previously generated backup archive here. To reset the firmware to its initial state, click "Perform reset" (only possible with squashfs images).
Can I restore the configuration to extfs on a Raspberry Pi 4?
to restore to default you need the squashfs install rather than the ext4 version. It's not that hard to reflash the stock image on the SD card tho, less than 10 minutes
The hard part is getting my USB network dongle to work.
My doesn't it work with extfs?
I've actually since moved to the RPi4 since last time. In terms of getting it to work from the word go, using the Image Builder is best practice. I simply build with the packages I need ready to go and it's set for me from first install. Don't need to finagle with managing kernel mods, network config or installing LuCi. https://openwrt.org/docs/guide-user/additional-software/imagebuilder It will generally automatically help you manage packages due to the nature of dependencies and such, but it's best practice to be a bit more explicit for backbone packages (Like LuCi, uhttpd, kernel mods). Honestly far easier than managing it from clean-slate images. I just used a Debian VM to create the build environment.