Description for large_blocks feature states the following at the end (verified manpages for 11.4-R, 12.1-R, and HEAD):
"Please note that booting from datasets that have recordsize greater than 128KB is NOT supported by the FreeBSD boot loader."
However, this has been fixed in r328866 more than 2 years ago.
A commit references this bug:
Date: Wed Jul 15 14:38:16 UTC 2020
New revision: 363224
zpool-features(7): Note that the boot loader has support for large_blocks
Since r304321 (-current: Aug 18, 2016) and r328866 (stable/11: Feb 5, 2018)
the FreeBSD loader has supported reading from datasets with the
large_blocks feature active.
Reported by: Anton Saietskii <firstname.lastname@example.org>
MFC after: 2 weeks
Sponsored by: Klara Inc.