diff --git a/nixos/lib/make-iso9660-image.sh b/nixos/lib/make-iso9660-image.sh
index 45cdef1ef4d..b7b1ab52a63 100644
--- a/nixos/lib/make-iso9660-image.sh
+++ b/nixos/lib/make-iso9660-image.sh
@@ -47,7 +47,8 @@ if test -n "$bootable"; then
 
     isoBootFlags="-eltorito-boot ${bootImage}
                   -eltorito-catalog .boot.cat
-                  -no-emul-boot -boot-load-size 4 -boot-info-table"
+                  -no-emul-boot -boot-load-size 4 -boot-info-table
+                  --sort-weight 1 /isolinux" # Make sure isolinux is near the beginning of the ISO
 fi
 
 if test -n "$usbBootable"; then
@@ -112,7 +113,7 @@ xorriso="xorriso
  -r
  -path-list pathlist
  --sort-weight 0 /
- --sort-weight 1 /isolinux" # Make sure isolinux is near the beginning of the ISO
+"
 
 $xorriso -output $out/iso/$isoName
 
diff --git a/nixos/modules/installer/cd-dvd/iso-image.nix b/nixos/modules/installer/cd-dvd/iso-image.nix
index aa8003fef2c..9475da23b1f 100644
--- a/nixos/modules/installer/cd-dvd/iso-image.nix
+++ b/nixos/modules/installer/cd-dvd/iso-image.nix
@@ -50,7 +50,7 @@ let
     finalCfg = {
       name = "NixOS ${config.system.nixos.label}${config.isoImage.appendToMenuLabel}";
       params = "init=${config.system.build.toplevel}/init ${additional} ${toString config.boot.kernelParams}";
-      image = "/boot/bzImage";
+      image = "/boot/${config.system.boot.loader.kernelFile}";
       initrd = "/boot/initrd";
     };
   in
@@ -163,7 +163,7 @@ let
       cp -v ${pkgs.refind}/share/refind/refind_x64.efi $out/EFI/boot/
       ''
     else
-      "# No refind for ia32"
+      "# No refind for ${targetArch}"
   ;
 
   grubMenuCfg = ''
@@ -222,18 +222,34 @@ let
   efiDir = pkgs.runCommand "efi-directory" {} ''
     mkdir -p $out/EFI/boot/
 
+    # ALWAYS required modules.
     MODULES="fat iso9660 part_gpt part_msdos \
              normal boot linux configfile loopback chain halt \
-             efifwsetup efi_gop efi_uga \
+             efifwsetup efi_gop \
              ls search search_label search_fs_uuid search_fs_file \
              gfxmenu gfxterm gfxterm_background gfxterm_menu test all_video loadenv \
              exfat ext2 ntfs btrfs hfsplus udf \
              videoinfo png \
              echo serial \
             "
+
+    echo "Building GRUB with modules:"
+    for mod in $MODULES; do
+      echo " - $mod"
+    done
+
+    # Modules that may or may not be available per-platform.
+    echo "Adding additional modules:"
+    for mod in efi_uga; do
+      if [ -f ${pkgs.grub2_efi}/lib/grub/${pkgs.grub2_efi.grubTarget}/$mod.mod ]; then
+        echo " - $mod"
+        MODULES+=" $mod"
+      fi
+    done
+
     # Make our own efi program, we can't rely on "grub-install" since it seems to
     # probe for devices, even with --skip-fs-probe.
-    ${pkgs.grub2_efi}/bin/grub-mkimage -o $out/EFI/boot/${if targetArch == "x64" then "bootx64" else "bootia32"}.efi -p /EFI/boot -O ${if targetArch == "x64" then "x86_64" else "i386"}-efi \
+    ${pkgs.grub2_efi}/bin/grub-mkimage -o $out/EFI/boot/boot${targetArch}.efi -p /EFI/boot -O ${pkgs.grub2_efi.grubTarget} \
       $MODULES
     cp ${pkgs.grub2_efi}/share/grub/unicode.pf2 $out/EFI/boot/
 
@@ -344,12 +360,19 @@ let
       ${pkgs.dosfstools}/sbin/fsck.vfat -vn "$out"
     ''; # */
 
-  targetArch = if pkgs.stdenv.isi686 then
-    "ia32"
-  else if pkgs.stdenv.isx86_64 then
-    "x64"
-  else
-    throw "Unsupported architecture";
+  # Name used by UEFI for architectures.
+  targetArch =
+    if pkgs.stdenv.isi686 then
+      "ia32"
+    else if pkgs.stdenv.isx86_64 then
+      "x64"
+    else if pkgs.stdenv.isAarch64 then
+      "aa64"
+    else
+      throw "Unsupported architecture";
+
+  # Syslinux (and isolinux) only supports x86-based architectures.
+  canx86BiosBoot = pkgs.stdenv.isi686 || pkgs.stdenv.isx86_64;
 
 in
 
@@ -483,9 +506,9 @@ in
     # here and it causes a cyclic dependency.
     boot.loader.grub.enable = false;
 
-    # !!! Hack - attributes expected by other modules.
-    system.boot.loader.kernelFile = "bzImage";
-    environment.systemPackages = [ pkgs.grub2 pkgs.grub2_efi pkgs.syslinux ];
+    environment.systemPackages = [ pkgs.grub2 pkgs.grub2_efi ]
+      ++ optional canx86BiosBoot pkgs.syslinux
+    ;
 
     # In stage 1 of the boot, mount the CD as the root FS by label so
     # that we don't need to know its device.  We pass the label of the
@@ -556,13 +579,7 @@ in
     # Individual files to be included on the CD, outside of the Nix
     # store on the CD.
     isoImage.contents =
-      [ { source = pkgs.substituteAll  {
-            name = "isolinux.cfg";
-            src = pkgs.writeText "isolinux.cfg-in" isolinuxCfg;
-            bootRoot = "/boot";
-          };
-          target = "/isolinux/isolinux.cfg";
-        }
+      [
         { source = config.boot.kernelPackages.kernel + "/" + config.system.boot.loader.kernelFile;
           target = "/boot/" + config.system.boot.loader.kernelFile;
         }
@@ -572,9 +589,6 @@ in
         { source = config.system.build.squashfsStore;
           target = "/nix-store.squashfs";
         }
-        { source = "${pkgs.syslinux}/share/syslinux";
-          target = "/isolinux";
-        }
         { source = config.isoImage.efiSplashImage;
           target = "/EFI/boot/efi-background.png";
         }
@@ -584,6 +598,17 @@ in
         { source = pkgs.writeText "version" config.system.nixos.label;
           target = "/version.txt";
         }
+      ] ++ optionals canx86BiosBoot [
+        { source = pkgs.substituteAll  {
+            name = "isolinux.cfg";
+            src = pkgs.writeText "isolinux.cfg-in" isolinuxCfg;
+            bootRoot = "/boot";
+          };
+          target = "/isolinux/isolinux.cfg";
+        }
+        { source = "${pkgs.syslinux}/share/syslinux";
+          target = "/isolinux";
+        }
       ] ++ optionals config.isoImage.makeEfiBootable [
         { source = efiImg;
           target = "/boot/efi.img";
@@ -591,7 +616,7 @@ in
         { source = "${efiDir}/EFI";
           target = "/EFI";
         }
-      ] ++ optionals config.boot.loader.grub.memtest86.enable [
+      ] ++ optionals (config.boot.loader.grub.memtest86.enable && canx86BiosBoot) [
         { source = "${pkgs.memtest86plus}/memtest.bin";
           target = "/boot/memtest.bin";
         }
@@ -606,9 +631,10 @@ in
     # Create the ISO image.
     system.build.isoImage = pkgs.callPackage ../../../lib/make-iso9660-image.nix ({
       inherit (config.isoImage) isoName compressImage volumeID contents;
-      bootable = true;
+      bootable = canx86BiosBoot;
       bootImage = "/isolinux/isolinux.bin";
-    } // optionalAttrs config.isoImage.makeUsbBootable {
+      syslinux = if canx86BiosBoot then pkgs.syslinux else null;
+    } // optionalAttrs (config.isoImage.makeUsbBootable && canx86BiosBoot) {
       usbBootable = true;
       isohybridMbrImage = "${pkgs.syslinux}/share/syslinux/isohdpfx.bin";
     } // optionalAttrs config.isoImage.makeEfiBootable {