UEFI booting from NVMe on a Dell R340

#
# refind.conf
# Configuration file for the rEFInd boot menu
#

# Timeout in seconds for the main menu screen. Setting the timeout to 0
# disables automatic booting (i.e., no timeout). Setting it to -1 causes
# an immediate boot to the default OS *UNLESS* a keypress is in the buffer
# when rEFInd launches, in which case that keypress is interpreted as a
# shortcut key. If no matching shortcut is found, rEFInd displays its
# menu with no timeout.
#
timeout 3

# Whether to store rEFInd's rEFInd-specific variables in NVRAM (1, true,
# or on) or in files in the "vars" subdirectory of rEFInd's directory on
# disk (0, false, or off). Using NVRAM works well with most computers;
# however, it increases wear on the motherboard's NVRAM, and if the EFI
# is buggy or the NVRAM is old and worn out, it may not work at all.
# Storing variables on disk is a viable alternative in such cases, or
# if you want to minimize wear and tear on the NVRAM; however, it won't
# work if rEFInd is stored on a filesystem that's read-only to the EFI
# (such as an HFS+ volume), and it increases the risk of filesystem
# damage. Note that this option affects ONLY rEFInd's own variables,
# such as the PreviousBoot, HiddenTags, HiddenTools, and HiddenLegacy
# variables. It does NOT affect Secure Boot or other non-rEFInd
# variables.
# Default is true
#
use_nvram false

# Which non-bootloader tools to show on the tools line, and in what
# order to display them:
#  shell            - the EFI shell (requires external program; see rEFInd
#                     documentation for details)
#  memtest          - the memtest86 program, in EFI/tools, EFI/memtest86,
#                     EFI/memtest, EFI/tools/memtest86, EFI/tools/memtest,
#                     or a boot loader's directory
#  gptsync          - the (dangerous) gptsync.efi utility (requires external
#                     program; see rEFInd documentation for details)
#  gdisk            - the gdisk partitioning program
#  apple_recovery   - boots the Apple Recovery HD partition, if present
#  windows_recovery - boots an OEM Windows recovery tool, if present
#                     (see also the windows_recovery_files option)
#  mok_tool         - makes available the Machine Owner Key (MOK) maintenance
#                     tool, MokManager.efi, used on Secure Boot systems
#  csr_rotate       - adjusts Apple System Integrity Protection (SIP)
#                     policy. Requires "csr_values" to be set.
#  install          - an option to install rEFInd from the current location
#                     to another ESP
#  bootorder        - adjust the EFI's (NOT rEFInd's) boot order
#  about            - an "about this program" option
#  hidden_tags      - manage hidden tags
#  exit             - a tag to exit from rEFInd
#  shutdown         - shuts down the computer (a bug causes this to reboot
#                     many UEFI systems)
#  reboot           - a tag to reboot the computer
#  firmware         - a tag to reboot the computer into the firmware's
#                     user interface (ignored on older computers)
#  fwupdate         - a tag to update the firmware; launches the fwupx64.efi
#                     (or similar) program
#  netboot          - launch the ipxe.efi tool for network (PXE) booting
# Default is shell,memtest,gdisk,apple_recovery,windows_recovery,mok_tool,about,hidden_tags,shutdown,reboot,firmware,fwupdate
# To completely disable scanning for all tools, provide a showtools line
# with no options.
#
showtools install, shell, bootorder, gdisk, memtest, mok_tool, apple_recovery, windows_recovery, about, hidden_tags, reboot, exit, firmware, fwupdate

# Which types of boot loaders to search, and in what order to display them:
#  internal      - internal EFI disk-based boot loaders
#  external      - external EFI disk-based boot loaders
#  optical       - EFI optical discs (CD, DVD, etc.)
#  netboot       - EFI network (PXE) boot options
#  hdbios        - BIOS disk-based boot loaders
#  biosexternal  - BIOS external boot loaders (USB, eSATA, etc.)
#  cd            - BIOS optical-disc boot loaders
#  manual        - use stanzas later in this configuration file
#  firmware      - boot EFI programs set in the firmware's NVRAM
# Note that the legacy BIOS options require firmware support, which is
# not present on all computers.
# The netboot option is experimental and relies on the ipxe.efi and
# ipxe_discover.efi program files.
# On UEFI PCs, default is internal,external,optical,manual
# On Macs, default is internal,hdbios,external,biosexternal,optical,cd,manual
#
#scanfor internal,external,optical,manual,firmware
scanfor internal,external

# Filename prefixes that indicate a file is a Linux kernel. Files that
# begin with any of these strings are treated as Linux kernels, if they
# are also EFI boot loaders. To include the default string, use "+"
# Default is "vmlinuz,bzImage,kernel", except on ARM64, where it is
# "vmlinuz,Image,kernel".
#
linux_prefixes EFI/systemd/systemd-bootx64.efi

# Sample manual configuration stanzas. Each begins with the "menuentry"
# keyword followed by a name that's to appear in the menu (use quotes
# if you want the name to contain a space) and an open curly brace
# ("{"). Each entry ends with a close curly brace ("}"). Common
# keywords within each stanza include:
#
#  volume    - identifies the filesystem from which subsequent files
#              are loaded. You can specify the volume by filesystem
#              label, by partition label, or by partition GUID number
#              (but NOT yet by filesystem UUID number).
#  loader    - identifies the boot loader file
#  initrd    - Specifies an initial RAM disk file
#  icon      - specifies a custom boot loader icon
#  ostype    - OS type code to determine boot options available by
#              pressing Insert. Valid values are "MacOS", "Linux",
#              "Windows", and "XOM". Case-sensitive.
#  graphics  - set to "on" to enable graphics-mode boot (useful
#              mainly for MacOS) or "off" for text-mode boot.
#              Default is auto-detected from loader filename.
#  options   - sets options to be passed to the boot loader; use
#              quotes if more than one option should be passed or
#              if any options use characters that might be changed
#              by rEFInd parsing procedures (=, /, #, or tab).
#  disabled  - use alone or set to "yes" to disable this entry.
#
# Note that you can use either DOS/Windows/EFI-style backslashes (\)
# or Unix-style forward slashes (/) as directory separators. Either
# way, all file references are on the ESP from which rEFInd was
# launched.
# Use of quotes around parameters causes them to be interpreted as
# one keyword, and for parsing of special characters (spaces, =, /,
# and #) to be disabled. This is useful mainly with the "options"
# keyword. Use of quotes around parameters that specify filenames is
# permissible, but you must then use backslashes instead of slashes,
# except when you must pass a forward slash to the loader, as when
# passing a root= option to a Linux kernel.
menuentry "systemd-boot" {
    loader /EFI/systemd/systemd-bootx64.efi
    icon /EFI/refind/icons/os_arch.png
}