This bug was fixed in the package partman-auto - 134ubuntu1.3
--------------- partman-auto (134ubuntu1.3) xenial; urgency=medium
* Bump minimum and maximum sizes for /boot partitions on default, x86, and EFI platforms to a minimum of 512Mb and maximum of 768Mb. (LP: #1716999)
-- Mathieu Trudel-Lapierre <email address hidden> Fri, 06 Jul 2018 12:52:33 -0400
This bug was fixed in the package partman-auto - 134ubuntu1.3
---------------
partman-auto (134ubuntu1.3) xenial; urgency=medium
* Bump minimum and maximum sizes for /boot partitions on default, x86, and
EFI platforms to a minimum of 512Mb and maximum of 768Mb. (LP: #1716999)
-- Mathieu Trudel-Lapierre <email address hidden> Fri, 06 Jul 2018 12:52:33 -0400