I assume your RTFM means set it to legacy and use /etc/fstab? Seems ucmbersome, but it's worth a try.
- [gentoo-user] preserving zpool mountpoint on boot? Nuno Magalhães
- Re: [gentoo-user] preserving zpool mountpoint on... Volker Armin Hemmann
- Re: [gentoo-user] preserving zpool mountpoin... Nuno Magalhães
- Re: [gentoo-user] preserving zpool mount... Volker Armin Hemmann