Using systemd in initramfs

[Shamino0]

Hi. Is there a known-good procedure for replacing the tegra-minimal-initramfs image with one that uses systemd? More specifically, I want to be able to use the systemd.virtual=overlay mechanism to make a read-only root file system with changes going into tmpfs.

Later on, I will want to be able to use other systemd services at that layer, for things like validating and encrypting the root file system.

I've found tips for how to do this on generic Linux systems, but I'm not sure how well they will apply to something based on meta-tegra.

[kekiefer]

There’s nothing preventing you from replacing the existing minimal initramfs image with your own. You can refer to what systemd-initramfs in DISTRO_FEATURES does in core-image-initramfs-boot, and either just use this as the base of your own custom initramfs image, or make your own similar based on the initramfs framework.

[Shamino0]

Yes, but there are features of the meta-tegra layer, including:

• UEFI code signing
• A/B boot-slot selection

Which don't come for free. Using lots of web research, I was able to come up with something that mostly works (I'm still working on it), so I was wondering if there is an established best-common-practice for this.

[kekiefer]

No, I haven’t seen this come up. Though as you pointed out there’s only a few concerns that need to be handled. Maybe something could be included in this layer that would be helpful here, besides the provided minimal initramfs example?