Comment 11 for bug 1808056

On the kernel side, the switch to a compressed kernel is a trivial change:

diff --git a/debian.raspi2/rules.d/arm64.mk b/debian.raspi2/rules.d/arm64.mk
index ada61b8..9f82433 100644
--- a/debian.raspi2/rules.d/arm64.mk
+++ b/debian.raspi2/rules.d/arm64.mk
@@ -3,7 +3,7 @@ build_arch = arm64
 header_arch = arm64
 defconfig = defconfig
 flavours = raspi2
-build_image = Image
+build_image = Image.gz
 kernel_file = arch/$(build_arch)/boot/Image
 install_file = vmlinuz
 no_dumpfile = true

Feel free to send such a change to the kernel ml once userspace issues (classic and core) are sorted out.