Comment 15 for bug 1890803

fwiw, fstab is essentially how overlayroot "communicates" to the system after pivot root about the different mounts.

You'll need to debug further to see whats going wrong. try using init=/bin/bash, and /run/initramfs/overlayroot.log should have more information.

You can also turn on debug with overlayroot=tmpfs,debug=1 then the 'debug' messages will go to the console.

But really I think this is just overlayroot not supporting this setup due to newer systemd or lack of fstab.