Just to be clear if you are going from 3.x to 4.x Update uboot first with the instructions from the link. You then want to reboot and check that the uboot firmware updated. Once that is done then update with the .IMG file ( I would use the Date Compiled: 2022-11-14 02:57:37 (UTC-05:00)SHA256: 6d3fcfde9f7b49aba32bce540ff698bcefc1849ae6bc8b9fc49682b123af9d56 This is a stable build 4.1.0. do a fresh install (do not keep settings) setup how you want and make a backup in LuCi of the config file and reboot. If you want to load a 4.2.0 beta or snapshot you can now do it from the GUI
Common problems with uboot are:
More then one device is connected to the wired connection of the router
You need to hold the power button/reset button before powering the router.
Use a private browser window when doing Uboot(this prevents cached pages)

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