Светлана Степанковская meets Tezcatlipoca.

Intending to give a spin to Metztli Reiser4 on a bare metal server, about a year ago, I had deposited 20 per cent of the promotional cost to a cloud/metal infrastructure hosting provider. The other 80 percent was on the provider during the advertised monthly period. Unlike an older Dell bare metal server that I had given a spin to in the past with another provider --where I had to open a ticket and request temporarily an IP/KVM device attached to the server and for the provider's technicians to download Metztli Reiser4 ISO image and make it available as a CDROM device-- this provider offered no such enablement. Although this provider allowed custom images in their cloud instances, when I inquired about Metztli Reiser4 on their bare metal servers they said there was no provision for custom images at the time --the feature was planned as a future offering-- I was told. Duh!, I thought to myself. I had just lost some money in a foolish deposit.

I returned to same provider approximately one year later as their campaign offered a 60 percent trial discount on metal servers; yet still there was no provision for custom images. Nevertheless, I needed a server for an email migration task as the Google Compute Engine (GCE) images that I usually deploy do not allow port 25 to be open. I had even tried with a relay service to no avail --as port 25 needs to be open to receive email. Accordingly, I deposited another 20 percent with this provider to have the 40 percent required to complete a one month trial period of a metal server for my email immediate task needs.

I knew I had to select a plain vanilla Debian x64 during the provisioning process; notwithstanding, upon logging into the environment I was taken aback realizing the entire Debian system disk was formatted in ext4 (the second disk was unformatted). Unlike the moralistic elite inside and outside Free and Open Source (FOSS) ecosystems, I have come to appreciate reiser4 on its technical meritocracy. I have never lost any data in the five(5) to six(6) years I have used this superb filesystem in my daily computing environment. I have come to appreciate reiser4 unmatched reliability and resiliency features --as well as its quirks-- and, logically, there was this odd uneasiness about being forced to work on this strange root file system. A feeling the traditionally vulnerable people of Venezuela --unlike the racist Spanish scum oligarchies usurping power throughout so called 'Latin'America-- must be experiencing as USA leads the West attempts to impose a spurious president upon Venezuela's sovereignty. Hence, I began to explore the possibility of replacing this alien file system --an imposition on me by the FOSS ethically entitled overlords who, besides pretending their corporate employers and/or host countries' historical deeds are a 'paradigm of ethical and moral virtuosity' (especially in the West ) -- effectively blacklist predetermined software by dictating to their GNU Parted...er, XYZ project's herd what 'ethical and moral virtuosity' their Linux distributions' file system should default to.

During my online research quest I stumbled upon sbootmgr from the details in an old post: Making grub boot the CD-ROM which I thought its menu (if it worked) would also list the second hard disk in my remotely provisioned metal server. Notwithstanding, after chasing the old Slackware's sbootmgr.dsk¹ from an official repository and combining it with memdisk.bin from Debian in an OpenSuSE virtual machine (VM), it killed the whole VirtualBox type 2 Hypervisor. Not something you want to do in your remote server. I realized I needed something more recent.

And then I came across How to Boot Linux ISO Images Directly From Your Hard Drive, written in 2017. It began to make sense, as I read the post, its potential adaptation to my current situation. Heck! I did not even have to guess the inner structure of Metztli Reiser4 as whenever I build the netboot custom image a tarred version of the Debian -based installer is created as well. I only needed to attempt, after iterative inductive feedback, a reference to the correct components in the netboot file structure that was acceptable to GRUB bootloader.

As previously mentioned, this metal server came with two SSD hard disks. The first SSD had the ext4 -formatted Debian 9 (Stretch) whereas the second SSD hard drive was unformatted. Yet both hard disks were previously initialized with MSDOS MBR; this fact was important when I began analyzing the custom GRUB entry.

I uploaded Metztli Reiser4 ISO to first hard disk home environment. Then I created a small five-hundred(500) MB partition at the beginning of the second SSD hard disk, formatted in ext2, and created an ISOs directory into which I subsequently copied over Metztli Reiser4 ISO image.

The following fragment, based on my most recent Metztli Reiser4 build of my custom Debian-Installer (d-i), was the minimum for an 'Expert install'. A tiny text editor, like xvi [download], might be used to open for editing the file /etc/grub.d/40_custom in existing vanilla Debian default operating system distribution of the metal server automatically provisioned for me:

menuentry 'Metztli Reiser4 Expert install' {
set isofile='metztli-reiser4.iso'
insmod gzio
insmod part_msdos²
insmod ext2³
insmod loopback
loopback loop (hd1,msdos1⁴)/ISOs/$isofile
linux (loop)/linux priority=low vga=788 ---
initrd (loop)/initrd.gz
}
I saved the above modifications (if copy-pasting please make sure to edit out the superscript numbers from the result) and closed xvi editing session.
Then, as root or with sudo privilege executed the command:

Shell

A few observations --as indicated by the superscripts above-- are in order:
²Had the second disk not been initialized in MSDOS MBR but in Globally Unique Identifiers (GUID) Partition Table (GPT), the above relevant directive would be:
insmod part_gpt

³Had the second hard disk partition not been formatted in ext2 but, say, jfs, we would write:
insmod jfs

⁴Again, had the second disk not been initialized in MSDOS MBR but in Globally Unique Identifiers (GUID) Partition Table (GPT), I would have written:
loopback loop (hd1,gpt1)

i.e., if it were first(1) jfs formatted GPT partition:
menuentry 'Metztli Reiser4 Expert install' {
set isofile='metztli-reiser4.iso'
insmod gzio
insmod part_gpt
insmod jfs
insmod loopback
loopback loop (hd0,gpt1)/ISOs/$isofile
linux (loop)/linux priority=low vga=788 ---
initrd (loop)/initrd.gz
}

because
...in a GRUB device name, the disk numbers start counting at 0 and the partition numbers start counting at 1'
How to Boot Linux ISO Images Directly From Your Hard Drive

Above fragment I wrote to /etc/grub.d/40_custom was gleaned from Metztli Reiser4 ISO image, more concisely,
./debian-installer/amd64/grub/grub.cfg
found within netboot structure:

Shell

./
./debian-installer/
./debian-installer/amd64/
./debian-installer/amd64/boot-screens/
./debian-installer/amd64/boot-screens/adtxt.cfg
./debian-installer/amd64/boot-screens/exithelp.cfg
./debian-installer/amd64/boot-screens/f1.txt
./debian-installer/amd64/boot-screens/f10.txt
./debian-installer/amd64/boot-screens/f2.txt
./debian-installer/amd64/boot-screens/f3.txt
./debian-installer/amd64/boot-screens/f4.txt
./debian-installer/amd64/boot-screens/f5.txt
./debian-installer/amd64/boot-screens/f6.txt
./debian-installer/amd64/boot-screens/f7.txt
./debian-installer/amd64/boot-screens/f8.txt
./debian-installer/amd64/boot-screens/f9.txt
./debian-installer/amd64/boot-screens/ldlinux.c32
./debian-installer/amd64/boot-screens/libcom32.c32
./debian-installer/amd64/boot-screens/libutil.c32
./debian-installer/amd64/boot-screens/menu.cfg
./debian-installer/amd64/boot-screens/prompt.cfg
./debian-installer/amd64/boot-screens/rqtxt.cfg
./debian-installer/amd64/boot-screens/splash.png
./debian-installer/amd64/boot-screens/stdmenu.cfg
./debian-installer/amd64/boot-screens/syslinux.cfg
./debian-installer/amd64/boot-screens/txt.cfg
./debian-installer/amd64/boot-screens/vesamenu.c32
./debian-installer/amd64/bootnetx64.efi
./debian-installer/amd64/grub/
./debian-installer/amd64/grub/font.pf2
./debian-installer/amd64/grub/grub.cfg
./debian-installer/amd64/grub/x86_64-efi/
./debian-installer/amd64/grub/x86_64-efi/acpi.mod
./debian-installer/amd64/grub/x86_64-efi/adler32.mod
./debian-installer/amd64/grub/x86_64-efi/ahci.mod
./debian-installer/amd64/grub/x86_64-efi/all_video.mod
./debian-installer/amd64/grub/x86_64-efi/aout.mod
./debian-installer/amd64/grub/x86_64-efi/appleldr.mod
./debian-installer/amd64/grub/x86_64-efi/archelp.mod
./debian-installer/amd64/grub/x86_64-efi/at_keyboard.mod
./debian-installer/amd64/grub/x86_64-efi/ata.mod
./debian-installer/amd64/grub/x86_64-efi/backtrace.mod
./debian-installer/amd64/grub/x86_64-efi/bfs.mod
./debian-installer/amd64/grub/x86_64-efi/bitmap.mod
./debian-installer/amd64/grub/x86_64-efi/bitmap_scale.mod
./debian-installer/amd64/grub/x86_64-efi/blocklist.mod
./debian-installer/amd64/grub/x86_64-efi/boot.mod
./debian-installer/amd64/grub/x86_64-efi/bsd.mod
./debian-installer/amd64/grub/x86_64-efi/bswap_test.mod
./debian-installer/amd64/grub/x86_64-efi/btrfs.mod
./debian-installer/amd64/grub/x86_64-efi/bufio.mod
./debian-installer/amd64/grub/x86_64-efi/cat.mod
./debian-installer/amd64/grub/x86_64-efi/cbfs.mod
./debian-installer/amd64/grub/x86_64-efi/cbls.mod
./debian-installer/amd64/grub/x86_64-efi/cbmemc.mod
./debian-installer/amd64/grub/x86_64-efi/cbtable.mod
./debian-installer/amd64/grub/x86_64-efi/cbtime.mod
./debian-installer/amd64/grub/x86_64-efi/chain.mod
./debian-installer/amd64/grub/x86_64-efi/cmdline_cat_test.mod
./debian-installer/amd64/grub/x86_64-efi/cmp.mod
./debian-installer/amd64/grub/x86_64-efi/cmp_test.mod
./debian-installer/amd64/grub/x86_64-efi/command.lst
./debian-installer/amd64/grub/x86_64-efi/cpio.mod
./debian-installer/amd64/grub/x86_64-efi/cpio_be.mod
./debian-installer/amd64/grub/x86_64-efi/cpuid.mod
./debian-installer/amd64/grub/x86_64-efi/crc64.mod
./debian-installer/amd64/grub/x86_64-efi/crypto.lst
./debian-installer/amd64/grub/x86_64-efi/crypto.mod
./debian-installer/amd64/grub/x86_64-efi/cryptodisk.mod
./debian-installer/amd64/grub/x86_64-efi/cs5536.mod
./debian-installer/amd64/grub/x86_64-efi/ctz_test.mod
./debian-installer/amd64/grub/x86_64-efi/date.mod
./debian-installer/amd64/grub/x86_64-efi/datehook.mod
./debian-installer/amd64/grub/x86_64-efi/datetime.mod
./debian-installer/amd64/grub/x86_64-efi/disk.mod
./debian-installer/amd64/grub/x86_64-efi/diskfilter.mod
./debian-installer/amd64/grub/x86_64-efi/div.mod
./debian-installer/amd64/grub/x86_64-efi/div_test.mod
./debian-installer/amd64/grub/x86_64-efi/dm_nv.mod
./debian-installer/amd64/grub/x86_64-efi/echo.mod
./debian-installer/amd64/grub/x86_64-efi/efi_gop.mod
./debian-installer/amd64/grub/x86_64-efi/efi_uga.mod
./debian-installer/amd64/grub/x86_64-efi/efifwsetup.mod
./debian-installer/amd64/grub/x86_64-efi/efinet.mod
./debian-installer/amd64/grub/x86_64-efi/ehci.mod
./debian-installer/amd64/grub/x86_64-efi/elf.mod
./debian-installer/amd64/grub/x86_64-efi/eval.mod
./debian-installer/amd64/grub/x86_64-efi/exfat.mod
./debian-installer/amd64/grub/x86_64-efi/exfctest.mod
./debian-installer/amd64/grub/x86_64-efi/ext2.mod
./debian-installer/amd64/grub/x86_64-efi/extcmd.mod
./debian-installer/amd64/grub/x86_64-efi/fat.mod
./debian-installer/amd64/grub/x86_64-efi/file.mod
./debian-installer/amd64/grub/x86_64-efi/fixvideo.mod
./debian-installer/amd64/grub/x86_64-efi/font.mod
./debian-installer/amd64/grub/x86_64-efi/fs.lst
./debian-installer/amd64/grub/x86_64-efi/gcry_arcfour.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_blowfish.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_camellia.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_cast5.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_crc.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_des.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_dsa.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_idea.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_md4.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_md5.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_rfc2268.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_rijndael.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_rmd160.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_rsa.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_seed.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_serpent.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_sha1.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_sha256.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_sha512.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_tiger.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_twofish.mod
./debian-installer/amd64/grub/x86_64-efi/gcry_whirlpool.mod
./debian-installer/amd64/grub/x86_64-efi/geli.mod
./debian-installer/amd64/grub/x86_64-efi/gettext.mod
./debian-installer/amd64/grub/x86_64-efi/gfxmenu.mod
./debian-installer/amd64/grub/x86_64-efi/gfxterm.mod
./debian-installer/amd64/grub/x86_64-efi/gfxterm_background.mod
./debian-installer/amd64/grub/x86_64-efi/gfxterm_menu.mod
./debian-installer/amd64/grub/x86_64-efi/gptsync.mod
./debian-installer/amd64/grub/x86_64-efi/grub.cfg
./debian-installer/amd64/grub/x86_64-efi/gzio.mod
./debian-installer/amd64/grub/x86_64-efi/halt.mod
./debian-installer/amd64/grub/x86_64-efi/hashsum.mod
./debian-installer/amd64/grub/x86_64-efi/hdparm.mod
./debian-installer/amd64/grub/x86_64-efi/help.mod
./debian-installer/amd64/grub/x86_64-efi/hexdump.mod
./debian-installer/amd64/grub/x86_64-efi/hfs.mod
./debian-installer/amd64/grub/x86_64-efi/hfsplus.mod
./debian-installer/amd64/grub/x86_64-efi/hfspluscomp.mod
./debian-installer/amd64/grub/x86_64-efi/http.mod
./debian-installer/amd64/grub/x86_64-efi/iorw.mod
./debian-installer/amd64/grub/x86_64-efi/jfs.mod
./debian-installer/amd64/grub/x86_64-efi/jpeg.mod
./debian-installer/amd64/grub/x86_64-efi/keylayouts.mod
./debian-installer/amd64/grub/x86_64-efi/keystatus.mod
./debian-installer/amd64/grub/x86_64-efi/ldm.mod
./debian-installer/amd64/grub/x86_64-efi/legacy_password_test.mod
./debian-installer/amd64/grub/x86_64-efi/legacycfg.mod
./debian-installer/amd64/grub/x86_64-efi/linux.mod
./debian-installer/amd64/grub/x86_64-efi/linux16.mod
./debian-installer/amd64/grub/x86_64-efi/linuxefi.mod
./debian-installer/amd64/grub/x86_64-efi/loadbios.mod
./debian-installer/amd64/grub/x86_64-efi/loadenv.mod
./debian-installer/amd64/grub/x86_64-efi/loopback.mod
./debian-installer/amd64/grub/x86_64-efi/ls.mod
./debian-installer/amd64/grub/x86_64-efi/lsacpi.mod
./debian-installer/amd64/grub/x86_64-efi/lsefi.mod
./debian-installer/amd64/grub/x86_64-efi/lsefimmap.mod
./debian-installer/amd64/grub/x86_64-efi/lsefisystab.mod
./debian-installer/amd64/grub/x86_64-efi/lsmmap.mod
./debian-installer/amd64/grub/x86_64-efi/lspci.mod
./debian-installer/amd64/grub/x86_64-efi/lssal.mod
./debian-installer/amd64/grub/x86_64-efi/luks.mod
./debian-installer/amd64/grub/x86_64-efi/lvm.mod
./debian-installer/amd64/grub/x86_64-efi/lzopio.mod
./debian-installer/amd64/grub/x86_64-efi/macbless.mod
./debian-installer/amd64/grub/x86_64-efi/macho.mod
./debian-installer/amd64/grub/x86_64-efi/mdraid09.mod
./debian-installer/amd64/grub/x86_64-efi/mdraid09_be.mod
./debian-installer/amd64/grub/x86_64-efi/mdraid1x.mod
./debian-installer/amd64/grub/x86_64-efi/memrw.mod
./debian-installer/amd64/grub/x86_64-efi/minicmd.mod
./debian-installer/amd64/grub/x86_64-efi/minix2.mod
./debian-installer/amd64/grub/x86_64-efi/minix2_be.mod
./debian-installer/amd64/grub/x86_64-efi/minix3.mod
./debian-installer/amd64/grub/x86_64-efi/minix3_be.mod
./debian-installer/amd64/grub/x86_64-efi/minix_be.mod
./debian-installer/amd64/grub/x86_64-efi/mmap.mod
./debian-installer/amd64/grub/x86_64-efi/moddep.lst
./debian-installer/amd64/grub/x86_64-efi/morse.mod
./debian-installer/amd64/grub/x86_64-efi/mpi.mod
./debian-installer/amd64/grub/x86_64-efi/msdospart.mod
./debian-installer/amd64/grub/x86_64-efi/mul_test.mod
./debian-installer/amd64/grub/x86_64-efi/multiboot.mod
./debian-installer/amd64/grub/x86_64-efi/multiboot2.mod
./debian-installer/amd64/grub/x86_64-efi/nativedisk.mod
./debian-installer/amd64/grub/x86_64-efi/net.mod
./debian-installer/amd64/grub/x86_64-efi/newc.mod
./debian-installer/amd64/grub/x86_64-efi/normal.mod
./debian-installer/amd64/grub/x86_64-efi/ntfs.mod
./debian-installer/amd64/grub/x86_64-efi/ntfscomp.mod
./debian-installer/amd64/grub/x86_64-efi/odc.mod
./debian-installer/amd64/grub/x86_64-efi/offsetio.mod
./debian-installer/amd64/grub/x86_64-efi/ohci.mod
./debian-installer/amd64/grub/x86_64-efi/part_acorn.mod
./debian-installer/amd64/grub/x86_64-efi/part_amiga.mod
./debian-installer/amd64/grub/x86_64-efi/part_apple.mod
./debian-installer/amd64/grub/x86_64-efi/part_bsd.mod
./debian-installer/amd64/grub/x86_64-efi/part_dfly.mod
./debian-installer/amd64/grub/x86_64-efi/part_dvh.mod
./debian-installer/amd64/grub/x86_64-efi/part_gpt.mod
./debian-installer/amd64/grub/x86_64-efi/part_msdos.mod
./debian-installer/amd64/grub/x86_64-efi/part_plan.mod
./debian-installer/amd64/grub/x86_64-efi/part_sun.mod
./debian-installer/amd64/grub/x86_64-efi/part_sunpc.mod
./debian-installer/amd64/grub/x86_64-efi/partmap.lst
./debian-installer/amd64/grub/x86_64-efi/parttool.lst
./debian-installer/amd64/grub/x86_64-efi/parttool.mod
./debian-installer/amd64/grub/x86_64-efi/password.mod
./debian-installer/amd64/grub/x86_64-efi/password_pbkdf2.mod
./debian-installer/amd64/grub/x86_64-efi/pata.mod
./debian-installer/amd64/grub/x86_64-efi/pbkdf2.mod
./debian-installer/amd64/grub/x86_64-efi/pbkdf2_test.mod
./debian-installer/amd64/grub/x86_64-efi/pcidump.mod
./debian-installer/amd64/grub/x86_64-efi/play.mod
./debian-installer/amd64/grub/x86_64-efi/png.mod
./debian-installer/amd64/grub/x86_64-efi/priority_queue.mod
./debian-installer/amd64/grub/x86_64-efi/probe.mod
./debian-installer/amd64/grub/x86_64-efi/procfs.mod
./debian-installer/amd64/grub/x86_64-efi/progress.mod
./debian-installer/amd64/grub/x86_64-efi/raid5rec.mod
./debian-installer/amd64/grub/x86_64-efi/raid6rec.mod
./debian-installer/amd64/grub/x86_64-efi/random.mod
./debian-installer/amd64/grub/x86_64-efi/read.mod
./debian-installer/amd64/grub/x86_64-efi/reboot.mod
./debian-installer/amd64/grub/x86_64-efi/regexp.mod
./debian-installer/amd64/grub/x86_64-efi/reiserfs.mod
./debian-installer/amd64/grub/x86_64-efi/relocator.mod
./debian-installer/amd64/grub/x86_64-efi/romfs.mod
./debian-installer/amd64/grub/x86_64-efi/scsi.mod
./debian-installer/amd64/grub/x86_64-efi/serial.mod
./debian-installer/amd64/grub/x86_64-efi/setjmp.mod
./debian-installer/amd64/grub/x86_64-efi/setjmp_test.mod
./debian-installer/amd64/grub/x86_64-efi/setpci.mod
./debian-installer/amd64/grub/x86_64-efi/shift_test.mod
./debian-installer/amd64/grub/x86_64-efi/signature_test.mod
./debian-installer/amd64/grub/x86_64-efi/sleep.mod
./debian-installer/amd64/grub/x86_64-efi/sleep_test.mod
./debian-installer/amd64/grub/x86_64-efi/spkmodem.mod
./debian-installer/amd64/grub/x86_64-efi/squash4.mod
./debian-installer/amd64/grub/x86_64-efi/syslinuxcfg.mod
./debian-installer/amd64/grub/x86_64-efi/terminal.lst
./debian-installer/amd64/grub/x86_64-efi/terminal.mod
./debian-installer/amd64/grub/x86_64-efi/terminfo.mod
./debian-installer/amd64/grub/x86_64-efi/test.mod
./debian-installer/amd64/grub/x86_64-efi/test_blockarg.mod
./debian-installer/amd64/grub/x86_64-efi/testload.mod
./debian-installer/amd64/grub/x86_64-efi/testspeed.mod
./debian-installer/amd64/grub/x86_64-efi/tftp.mod
./debian-installer/amd64/grub/x86_64-efi/tga.mod
./debian-installer/amd64/grub/x86_64-efi/time.mod
./debian-installer/amd64/grub/x86_64-efi/tr.mod
./debian-installer/amd64/grub/x86_64-efi/trig.mod
./debian-installer/amd64/grub/x86_64-efi/true.mod
./debian-installer/amd64/grub/x86_64-efi/udf.mod
./debian-installer/amd64/grub/x86_64-efi/ufs1.mod
./debian-installer/amd64/grub/x86_64-efi/ufs1_be.mod
./debian-installer/amd64/grub/x86_64-efi/ufs2.mod
./debian-installer/amd64/grub/x86_64-efi/uhci.mod
./debian-installer/amd64/grub/x86_64-efi/usb.mod
./debian-installer/amd64/grub/x86_64-efi/usb_keyboard.mod
./debian-installer/amd64/grub/x86_64-efi/usbms.mod
./debian-installer/amd64/grub/x86_64-efi/usbserial_common.mod
./debian-installer/amd64/grub/x86_64-efi/usbserial_ftdi.mod
./debian-installer/amd64/grub/x86_64-efi/usbserial_pl2303.mod
./debian-installer/amd64/grub/x86_64-efi/usbserial_usbdebug.mod
./debian-installer/amd64/grub/x86_64-efi/usbtest.mod
./debian-installer/amd64/grub/x86_64-efi/verify.mod
./debian-installer/amd64/grub/x86_64-efi/video.lst
./debian-installer/amd64/grub/x86_64-efi/video.mod
./debian-installer/amd64/grub/x86_64-efi/video_bochs.mod
./debian-installer/amd64/grub/x86_64-efi/video_cirrus.mod
./debian-installer/amd64/grub/x86_64-efi/video_colors.mod
./debian-installer/amd64/grub/x86_64-efi/video_fb.mod
./debian-installer/amd64/grub/x86_64-efi/videoinfo.mod
./debian-installer/amd64/grub/x86_64-efi/videotest.mod
./debian-installer/amd64/grub/x86_64-efi/videotest_checksum.mod
./debian-installer/amd64/grub/x86_64-efi/xfs.mod
./debian-installer/amd64/grub/x86_64-efi/xnu.mod
./debian-installer/amd64/grub/x86_64-efi/xnu_uuid.mod
./debian-installer/amd64/grub/x86_64-efi/xnu_uuid_test.mod
./debian-installer/amd64/grub/x86_64-efi/xzio.mod
./debian-installer/amd64/grub/x86_64-efi/zfscrypt.mod
./debian-installer/amd64/initrd.gz
./debian-installer/amd64/linux
./debian-installer/amd64/pxelinux.0
./debian-installer/amd64/pxelinux.cfg/
./debian-installer/amd64/pxelinux.cfg/default -> ../boot-screens/syslinux.cfg
./ldlinux.c32 -> debian-installer/amd64/boot-screens/ldlinux.c32
./pxelinux.0 -> debian-installer/amd64/pxelinux.0
./pxelinux.cfg -> debian-installer/amd64/pxelinux.cfg
./version.info

On 'buggy' BIOS, installation of GRUB boot loader fails if your controller has a GPT partition.

For illustration, after creating an MBR backup, I used GNU fdisk utility to change the original MSDOS MBR -initialized second SSD hard disk to GPT. Subsequently, formatted the whole partition successfully in reiser4, as shown in subsequent very first clip below in addendum.

Notwithstanding, second (last) clip below in addendum exemplifies result if BIOS is 'buggy', i.e., GRUB boot loader fails to install into either hard disk of the same controller.

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¹I tried OS/2's loaddskf utility in an effort to peek into the innards of the sbootmgr.dsk.

GUID Partition Table.