No CDROM device available to customer, i.e., myself. Thus during acquisition of bare metal server I selected Debian 9 x64, which first SSD came formatted in ext4. I wanted Metztli Reiser4 but there was no provision for custom install image.

I made a note of Address, Netmask, Gateway, and Nameserver. I noted, as well the MSDOS MBR.

On the second SSD I created a small 500MB initial partition which I formatted in ext2. I copied over Metztli Reiser4 onto that partition. I knew I had to install Metztli Reiser4 as expert, thus, following a hint from: How to Boot Linux ISO Images Directly From Your Hard Drive, by trial and error I wrote to /etc/grub.d/40_custom the following:

menuentry 'Metztli Reiser4 Expert install' {
set isofile='metztli-reiser4.iso'
insmod gzio
insmod part_msdos
insmod ext2
insmod loopback
loopback loop (hd1,msdos1)/ISOs/$isofile
linux (loop)/linux priority=low vga=788 ---
initrd (loop)/initrd.gz
}

Executed with root privilege: update-grub
Rebooted the remote server -- as I opened up an iKVM console. Booting proceeded until GRUB screen came about from which I selected my entry Metztli Reiser4 Expert install... i.e., Metztli Reiser4, (SFRN) 4.0.2 on Supermicro 8-core Intel® Xeon® Processor E3-1270 v6
the rest is history ;-)

I have since built Metztli Reiser4 Linux 4.20.2, 'the Debian way' i.e., one node:
Linux huitzilopochtli 4.20.0-1+reiser4.0.2-amd64 #1 SMP Debian 4.20.2-1+reiser4.0.2 (2019-01-13) x86_64 GNU/Linux

Full report: https://metztli.blog/index.php/amatl/aN8