If it doesn't work try other browsers if you tested them with a chrome browser try to use firefox and apply the guide.
If it still doesn't work try this guide below this one you just need to send the command through the console
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https://bitcointalk.org/index.php?topic=2690140.msg34057256#msg34057256If it's still doesn't work maybe you are using a modified firmware or maybe the latest one.
Try to flash it through an SD card the SD card files can be found from this link below
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https://service.bitmain.com/support/download?product=Flashing%20SD%20card%20with%20imageAnd I hope this time it will work.