OMV on Pro/Ultra series -- a project

For the Pro and Ultra series units with their limited RAM and processors, I think Open Media Vault (OMV) is the best option for an alternate OS.  I'm looking at how to install it without needing the serial console, if possible.  Most importantly, I want it to boot without having to hold the reset button to boot from USB.  It won't be an "OMV on ReadyNAS for Dummies" exactly, but I hope will be for those  with a minimum amount of Linux experience -- as close to a "cookbook" as possible.  And I think the need for the console may scare away a lot of users, which is why I'd like to avoid it.

I'm posting here to see if anyone has explored any aspects of my plan to make it easier for me to find an answer or realize what I want to do just won't work and stop wasting my time.  So, if you're more of a Linux guru than I and would like to help, please reply.  Though I know a lot WRT the Linux command line, I've never done an install other than the normal interactive one on a unit or VM with a display.

My research says that the only way to have this drive/partition configuration  in OMV is to install from an existing Debian instance.  Otherwise, OMV expects a dedicated OS drive (which the flash is too small for).  And it's also how to install OMV via SSH.

So here is my thought:  Using GRUB as the boot loader, install Debian with GRUB itself on the internal flash but /boot, / (root), swap, and /data on the drives in RAID.  Specifically, I know GRUB can support MDADM RAID and I would make /boot and / EXT4 on MDADM RAID and /data as BTRFS on MDADM RAID, partly duplicating the ReadyNASOS partitioning scheme.  / would obviously need to be bigger.  /boot, /, and swap would be RAID0 with all drives included and /data would be  a RAID type appropriate to the number of drives and desired redundancy.

I believe that FAI (Fully Automated Installation) (see https://fai-project.org/FAIme/#) can be used to install Debian with that configuration without any interaction from the user and then OMV can be installed from that Debian instance via SSH.  So, no console needed.  FAI can definitely be configured to install Debian on MDADM RAID and EXT4 or BTRFS via a disk_config file.  It's unclear to me right now if I need to add any GRUB commands to do so.  FAI also allows you to install additional packages, so I believe openssh-server  can be installed that way to allow SSH access without interaction.

My plan is to try this first on a VM, maybe in steps (do an interactive install to the desired configuration before trying to do it with FAI).  That won't be definitive because there is no real flash memory, but it will let me debug any major Oopses without bricking a real NAS.  Then, I have several NAS on which I can try it, so long as I verify a USB recovery can go back to ReadyNASOS.

This should also be able to serve as at least a starting point for other Intel based models -- maybe it can be made to work on all.

While there is a lot more to do for it, it could even act as a starting point for some ARMHF based units (probably just 200 series, not 100).  But I'm not the guy for ARM-based units.  While I don't believe the current OMV works on ARMHF, some older ones do.