On my unit, the NOR WP jumper was populated on arrival and remains there still. I am still not entirely sure how this jumper is used. It seems it should be in place in order for NOR boot loader to unlock/enable NOR flashing, and re-lock on exit, and then removed to prevent any inordinate NOR mods.
Blogic indicated he would clarify this in this thread Cautionary tale - bricked OpenWRT One on first day, but I haven’t seen anything yet to that effect.
In normal operation the NAND/NOR switch should be set to NAND, and to upgrade firmware I have used the method shown in https://one.openwrt.org/hardware/OpenWrtOne-HowTo.pdf under the topic I want to upgrade the firmware using a usb, also rebooting into the initramfs recovery mode and initiating a typical sysupgrade via both LuCI and ssh, as well as just running sysupgrade from the current firmware.
So SPI NOR is not touched by a firmware upgrade.