I am trying to build an RHCOS layer for the following case #03497390 with a newer kernel version and debug mode enabled by using the following Containerfile:

# Using a 4.12.21 image
# export OCP_VERSION="4.12.21"
# curl -s https://mirror.openshift.com/pub/openshift-v4/clients/ocp/$OCP_VERSION/release.txt | grep -m1 'rhel-coreos-8' | awk -F ' ' '{print $2}'
ARG rhel_coreos_release
FROM ${rhel_coreos_release}
RUN rpm-ostree cliwrap install-to-root /
# Env
ENV KERNEL_RPM="https://people.redhat.com/midu/.kernel-4.18.0-507.el8.x86_64/kernel-debug-4.18.0-507.el8.x86_64.rpm \
    https://people.redhat.com/midu/.kernel-4.18.0-507.el8.x86_64/kernel-debug-core-4.18.0-507.el8.x86_64.rpm \
    https://people.redhat.com/midu/.kernel-4.18.0-507.el8.x86_64/kernel-debug-modules-4.18.0-507.el8.x86_64.rpm \
    https://people.redhat.com/midu/.kernel-4.18.0-507.el8.x86_64/kernel-debug-modules-extra-4.18.0-507.el8.x86_64.rpm"
# Install hotfix rpm
RUN rpm-ostree override replace ${KERNEL_RPM} && \
    rpm-ostree cleanup -m && \
    cd /usr/lib/modules/4.18.0-507.el8.x86_64+debug/ && sed -i 's/\/boot\///g' .vmlinuz.hmac && \
    ostree container commit

The issue encountered is the following:
Use `rpm-ostree initramfs` to control client-side initramfs generation.
rpm-ostree: Note: This system is image (rpm-ostree) based.
rpm-ostree: Dropping privileges as `dracut` was executed with not "known safe" arguments.
rpm-ostree: You may invoke the real `dracut` binary in `/usr/libexec/rpm-ostree/wrapped/dracut`.
rpm-ostree: Continuing execution in 5 seconds.

dracut: No permission to write to /boot.
Found file: "var/lib/rpm-state/kernel/installing_core_4.18.0-507.el8.x86_64"
error: Found content in var
Error: error building at STEP "RUN rpm-ostree override replace ${KERNEL_RPM} &&     rpm-ostree cleanup -m &&     cd /usr/lib/modules/4.18.0-507.el8.x86_64+debug/ && sed -i 's/\/boot\///g' .vmlinuz.hmac &&     ostree container commit": error while running runtime: exit status 1

while adapting the previous Containerfile to the following:
# Using a 4.12.21 image
# export OCP_VERSION="4.12.21"
# curl -s https://mirror.openshift.com/pub/openshift-v4/clients/ocp/$OCP_VERSION/release.txt | grep -m1 'rhel-coreos-8' | awk -F ' ' '{print $2}'
ARG rhel_coreos_release
FROM ${rhel_coreos_release}
RUN rpm-ostree cliwrap install-to-root /
# Env
ENV KERNEL_RPM="https://people.redhat.com/midu/.kernel-4.18.0-507.el8.x86_64/kernel-debug-4.18.0-507.el8.x86_64.rpm \
    https://people.redhat.com/midu/.kernel-4.18.0-507.el8.x86_64/kernel-debug-core-4.18.0-507.el8.x86_64.rpm \
    https://people.redhat.com/midu/.kernel-4.18.0-507.el8.x86_64/kernel-debug-modules-4.18.0-507.el8.x86_64.rpm \
    https://people.redhat.com/midu/.kernel-4.18.0-507.el8.x86_64/kernel-debug-modules-extra-4.18.0-507.el8.x86_64.rpm"
# Install hotfix rpm RUN rpm-ostree override replace ${KERNEL_RPM} && \
    rpm-ostree cleanup -m && rm -rf /var/* && \
    cd /usr/lib/modules/4.18.0-507.el8.x86_64+debug/ && sed -i 's/\/boot\///g' .vmlinuz.hmac && \
    ostree container commit

the image its builed succesfully BUT once the layer its being applied to the OCP the new kernel its not loaded:
[core@master0 ~]$ oc get mc | grep -i side
master-side-kernel                          20m

[core@master0 ~]$ uname -r
4.18.0-372.58.1.el8_6.x86_64

4.12.21

100%

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I would expect to be able to load the debug kernel as the default kernel.