I'm going through the security hardening steps on a new, local instance of Sitecore 9.1.1 with identity server. I made the SHA512 change in the Sitecore web.config, and I ran the database script to reset the password/salt appropriately:
UPDATE aspnet_Membership
SET Password = 'K8N8GUW8UiNT2mPdjvuBDH+QmvA3R61M9buVvCwFHwtDjpMzTxs34lg0uQ0azCITqh6FkUZlX4kM72lsAyuyXQ==',
PasswordSalt = 'p5B6HOWKt0ctMZaSNXTlfw=='
FROM aspnet_Membership m INNER JOIN aspnet_Users u ON m.UserId = u.UserId
WHERE u.UserName = 'sitecore\Admin'
However, I still cannot log into the CM. I'm guessing something else needs changing on the identity server side, but I don't see any references to SHA512 in that code. There was a reference online regarding an appsettings.json file for identity service in relation to Commerce, but not XP0, and that file doesn't exist that I can see.