man mysqld:
===========================8<==============================
-Sg|--skip-grant-tables
This option causes the server not to use the privilege system at
all. This gives everyone full access to all databases! (You can
tell a running server to start using the grant tables again by
executing mysqladmin flush-privileges or mysqladmin reload.)
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запускаем, меняем пароль root при помощи update, запускаем по-нормальному, все.