This bug was fixed in the package initramfs-tools - 0.133ubuntu4
--------------- initramfs-tools (0.133ubuntu4) eoan; urgency=medium
* Switch default initramfs compression to lz4, faster than the current default gzip. LP: #1831736
-- Dimitri John Ledkov <email address hidden> Wed, 05 Jun 2019 13:23:29 +0100
This bug was fixed in the package initramfs-tools - 0.133ubuntu4
---------------
initramfs-tools (0.133ubuntu4) eoan; urgency=medium
* Switch default initramfs compression to lz4, faster than the current
default gzip. LP: #1831736
-- Dimitri John Ledkov <email address hidden> Wed, 05 Jun 2019 13:23:29 +0100