Comment 1 for bug 1902287

https://bugs.launchpad.net/subiquity/+bug/1817066 suggests that subiquity supports installing two EFI system partitions (ESPs), but I did not find that functionality when I was looking for it.

My suggestion with this bug report is that such should be the default behavior when setting up a system with RAID-1 (which in turn perhaps should be the default when you're installing on a system with two similarly-sized hard drives...).

In the mean time I'll look again for where subiquity supported multiple ESPs, or if someone knows how that is done they might point me and others in the right direction...