[yocto] Can't boot to initramfs

[Moritz Porst]

Hello,
I currently try to deploy a single rootfs update mechanism for my
embedded device. I can't boot to initramfs using either "break" or
"break=premount" (without quotes...). I tried this in systemd-boot and
grub-efi (always efi boot) but the boot process just continues normally.
If I insert at the same point e.g. "quiet" this argument is recognised.
I boot the .wic image with a separate boot partition from a USB stick.
in local.conf I have set:
INITRAMFS_IMAGE = "core-image-minimal-initramfs"
INITRAMFS_IMAGE_BUNDLE = "1"

In order to reduce complexity I now use the standard
core-image-minimal-initramfs without .bbappend. I can confirm (from
seeing the task) that bitbake bundled the kernel with the initramfs.

You can find the /var/log/dmesg here: https://pastebin.com/ya7iCtq7

To my understanding the initramfs should be embedded in /boot/bzImage.
However since I use an intel platform I also have a /boot/microcode.cpio
which gets loaded via "initrd /microcode.cpio". Removing this line in
grub does not enable me to get an initramfs prompt either (again, using
break as option).

Did I forget some configuration or do I have to put the break statement
at a very specific position within the "linux ..." boot command ? Do you
know which bitbake variables to check ? (both set in local.conf do not
get overwritten, already checked this). I got the thud branch checked
out in all my meta-layers except for meta-qt which is currently on
master branch.

Help is much appreciated !

Best regards
Moritz