I followed a suggestion posted on this site that resulted in an unbootable system. Not being allowed to comment, I deliberately violated policy and posted a comment as an answer. I would not have done this but I thought it was important to warn other people against trying the advice. In fairness the advice was listed as "not recommended" but contained no indication of actual danger. I don't think advice leading to this outcome belongs on this site, but with no other way to notate what had happened, I thought I was doing other users a service. I thought I raised a serious issue, and that issue has not been dealt with but buried.
I will try to play by the rules from now on, but the rules seem more restrictive than they should to me.