You should see a different web page with uboot as logo, note that the end of the url must end with uboot like in the documentation because otherwise you are on the restore the firmware page, u-boot is basically your core bios where openwrt boots from.

To add: make sure before you upload anything that the image is 100% u-boot compatible and not just a firmware there might be links in the documentation or here else just ping me with a reply, because updating u-boot is usually not a standard procedure, this can hard brick ur device, so do so only when it has something broken in u-boot known in flint, you should see it as a procedure you only will do once and never hope to do it again.

1 Like