So yes, this post was about utilizing the last Debian packaging for Linux kernel 5.5 series, i.e., 5.5.13, and applying upstream delta patches to bring it up to 5.5.15. However, as I was writing this post kernel 5.5.16 became available --which is what I will aim to patch and, subsequently, I will 'Add support for ZSTD-compressed kernel and initramfs' via a customized patch. And lastly, I will apply reiser4 for 5.5.5 patch --which still applies smoothly over kernel 5.5.15, and hopefully 5.5.16, and build our hacked kernel.