Acordig to switchbrew wen update the nintendo switch saccseful then burn fuses so on wii and wii u gives option to click ok but wat happen on switch is wen you see pop up update complite the console wil be restart wen see this pop up means its burn fuses so to not burn fuse just wen see updating please wait get readyhead on power button then wen pop up got quikly hold popwer button and now you can downgrade