"freeing initrd memory" pointed me in the right direction.
I have modified /etc/initramfs-tools/initramfs.conf short time before. changed "COMPRESS=bzip2" and got a smaller file in the file-system
moved back to "COMPRESS=zstd" , update-initramfs -u and got the original filesize. after reboot the effect with 10 sec delay was gone.
"freeing initrd memory" pointed me in the right direction.
I have modified /etc/initramfs- tools/initramfs .conf short time before.
changed "COMPRESS=bzip2" and got a smaller file in the file-system
moved back to "COMPRESS=zstd" , update-initramfs -u and got the original filesize.
after reboot the effect with 10 sec delay was gone.