It turns out that there *is* chroot handling in plymouth, and /usr/share/initramfs-tools/scripts/init-bottom/plymouth has code to run this. But for some reason, my /scripts/init-bottom/ORDER is missing any references to plymouth:
/scripts/init-bottom/udev [ -e /conf/param.conf ] && . /conf/param.conf
So we need to figure out why that's missing.
It turns out that there *is* chroot handling in plymouth, and /usr/share/ initramfs- tools/scripts/ init-bottom/ plymouth has code to run this. But for some reason, my /scripts/ init-bottom/ ORDER is missing any references to plymouth:
/scripts/ init-bottom/ udev
[ -e /conf/param.conf ] && . /conf/param.conf
So we need to figure out why that's missing.