I also did the same, I'm going to try to send it to get repaired by Nintendo for $99, I'm not sure if they can find out if it has been tampered with, but on Nintendo's repair website, they said that if they couldn't fix it they would give you a new one.
Hello, when it comes to step number 9, on my mounted drive there isn't anyhting that says USER, it just shows "Contents", "save", and "saveMeta". If you could respond ASAP, that would be greatly appreciated.