I'm using the Ubuntu Mainline Kernel Updater to keep my installs on mainline because I want to start helping uncover kernel bugs in early releases. I've been doing this since late 4.15 release cycle using the linked update script. Starting with the 4.17 release cycle the Ubuntu Kernel PPA has been missing the deb builds for the kernel itself since rc2 but they came back in rc4/5 with the unsigned name. I know on the mailing list there were patches surrounding root of trust during the boot process and if they should be tied to certain UEFI flags. I also know this involved signing kernel releases and drivers, so I suspect that may be the cause of the name change and therefore non-functioning script.
I was hoping to get some more insight as to where on the Ubuntu side I would receive communications regarding why certain RCs were incomplete and why the others changed. Obv Bionic dropped and I figured that might be the reason some were incomplete.
Should I just go ahead and patch the updater script to use the unsigned images? I'm not terribly concerned about the presence (or lack thereof) of the chain of trust feature.
Thanks
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Best Answer
Early -rcs commonly are not buildable due to upstream bugs. The later switch to -unsigned is deliberate and permenant for later versions. These relate to a change to have always signed kernels on full installed so the linux-image-* package now always contains a signed kernel if one exists. The unsigned kernel is shipped in linux-image-unsigned-*. These kernels are by definition always unsigned.