Found something interesting.
Bionic + 2048 MiB of RAM (bad):
[ 1.520243] Unpacking initramfs... [ 14.712821] Initramfs unpacking failed: broken padding [ 14.723088] Freeing initrd memory: 56636K
Bionic + 2049 MiB of RAM (good):
[ 0.752624] Unpacking initramfs... [ 5.572407] Freeing initrd memory: 56636K
Xenial HWE + 2048 MiB of RAM (bad):
[ 5.598647] Unpacking initramfs... [ 84.494431] Initramfs unpacking failed: junk in compressed archive [ 84.503565] Freeing initrd memory: 54564K
Found something interesting.
Bionic + 2048 MiB of RAM (bad):
[ 1.520243] Unpacking initramfs...
[ 14.712821] Initramfs unpacking failed: broken padding
[ 14.723088] Freeing initrd memory: 56636K
Bionic + 2049 MiB of RAM (good):
[ 0.752624] Unpacking initramfs...
[ 5.572407] Freeing initrd memory: 56636K
Xenial HWE + 2048 MiB of RAM (bad):
[ 5.598647] Unpacking initramfs...
[ 84.494431] Initramfs unpacking failed: junk in compressed archive
[ 84.503565] Freeing initrd memory: 54564K