There are scenarios when for ELI disk created without passphrase it is impossible to set one, since geli has to initialize number of PKCS#5v2 iterations, which attempt fail. This patch relaxes overly strict checks, allowing number of iteration to be set first time even if both keys are are already set.
This should fix: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=218512
, as much more simple alternative to: https://github.com/freebsd/freebsd/pull/109