diff --git a/metropolis/installer/BUILD.bazel b/metropolis/installer/BUILD.bazel
index 834dd9a..61e455e 100644
--- a/metropolis/installer/BUILD.bazel
+++ b/metropolis/installer/BUILD.bazel
@@ -40,7 +40,7 @@
 efi_unified_kernel_image(
     name = "kernel",
     cmdline = "console=ttyS0,115200 console=tty0 quiet",
-    initramfs = ":initramfs",
+    initrd = [":initramfs"],
     kernel = "//third_party/linux",
     os_release = ":installer-release-info",
     visibility = ["//visibility:public"],
diff --git a/metropolis/installer/test/BUILD.bazel b/metropolis/installer/test/BUILD.bazel
index 59c5803..c958ac2 100644
--- a/metropolis/installer/test/BUILD.bazel
+++ b/metropolis/installer/test/BUILD.bazel
@@ -34,7 +34,7 @@
 efi_unified_kernel_image(
     name = "kernel",
     cmdline = "loglevel=0 console=ttyS0",
-    initramfs = "//metropolis/installer:initramfs",
+    initrd = ["//metropolis/installer:initramfs"],
     kernel = "//third_party/linux",
     visibility = ["//visibility:private"],
 )
diff --git a/metropolis/node/build/efi.bzl b/metropolis/node/build/efi.bzl
index f9d0f44..5f6bfd6 100644
--- a/metropolis/node/build/efi.bzl
+++ b/metropolis/node/build/efi.bzl
@@ -10,7 +10,6 @@
     # Find the dependency paths to be passed to mkpayload.
     deps = {
         "linux": ctx.file.kernel,
-        "initrd": ctx.file.initramfs,
         "osrel": ctx.file.os_release,
         "splash": ctx.file.splash,
         "stub": ctx.file.stub,
@@ -39,6 +38,10 @@
             args.append("-{}={}".format(name, file.path))
             inputs.append(file)
 
+    for file in ctx.files.initrd:
+        args.append("-initrd={}".format(file.path))
+        inputs.append(file)
+
     # Append the output parameter separately, as it doesn't belong with the
     # runtime inputs.
     image = ctx.actions.declare_file(ctx.attr.name + ".efi")
@@ -73,9 +76,27 @@
         "cmdline": attr.string(
             doc = "The kernel commandline to be embedded.",
         ),
-        "initramfs": attr.label(
-            doc = "The initramfs to be embedded.",
-            allow_single_file = True,
+        "initrd": attr.label_list(
+            doc = """
+                List of payloads to concatenate and supply as the initrd parameter to Linux when it boots.
+                The name stems from the time Linux booted from an initial ram disk (initrd), but it's now
+                a catch-all for a bunch of different larger payload for early Linux initialization.
+
+                In Linux 5.15 this can first contain an arbitrary amount of uncompressed cpio archives
+                with directories being optional which is accessed by earlycpio. This is used for both
+                early microcode loading and ACPI table overrides. This can then be followed by an arbitrary
+                amount of compressed cpio archives (even with different compression methods) which will
+                together make up the initramfs. The initramfs is only booted into if it contains either
+                /init or whatever file is specified as init= in cmdline. Technically depending on kernel
+                flags you might be able to supply an actual initrd, i.e. an image of a disk loaded into
+                RAM, but that has been deprecated for nearly 2 decades and should really not be used.
+
+                For kernels designed to run on physical machines this should at least contain microcode,
+                optionally followed by a compressed initramfs. For kernels only used in virtualized
+                setups the microcode can be left out and if no initramfs is needed this option can
+                be omitted completely.
+                """,
+            allow_files = True,
         ),
         "os_release": attr.label(
             doc = """
diff --git a/metropolis/node/build/mkpayload/mkpayload.go b/metropolis/node/build/mkpayload/mkpayload.go
index 42ec062..aee3a81 100644
--- a/metropolis/node/build/mkpayload/mkpayload.go
+++ b/metropolis/node/build/mkpayload/mkpayload.go
@@ -22,12 +22,27 @@
 import (
 	"flag"
 	"fmt"
+	"io"
 	"log"
 	"os"
 	"os/exec"
 	"strings"
 )
 
+type stringList []string
+
+func (l *stringList) String() string {
+	if l == nil {
+		return ""
+	}
+	return strings.Join(*l, ", ")
+}
+
+func (l *stringList) Set(value string) error {
+	*l = append(*l, value)
+	return nil
+}
+
 var (
 	// sections contains VMAs and source files of the payload PE sections. The
 	// file path pointers will be filled in when the flags are parsed. It's used
@@ -46,6 +61,7 @@
 		"cmdline": {"a file containting additional kernel command line parameters", "0x30000", false, nil},
 		"splash":  {"a splash screen image in BMP format", "0x40000", false, nil},
 	}
+	initrdList      stringList
 	objcopy         = flag.String("objcopy", "", "objcopy executable")
 	stub            = flag.String("stub", "", "the EFI stub executable")
 	output          = flag.String("output", "", "objcopy output")
@@ -53,8 +69,12 @@
 )
 
 func main() {
+	flag.Var(&initrdList, "initrd", "Path to initramfs, can be given multiple times")
 	// Register parameters related to the EFI payload sections, then parse the flags.
 	for k, v := range sections {
+		if k == "initrd" { // initrd is special because it accepts multiple payloads
+			continue
+		}
 		v.file = flag.String(k, "", v.descr)
 		sections[k] = v
 	}
@@ -113,6 +133,30 @@
 		*sections["cmdline"].file = out.Name()
 	}
 
+	var initrdPath string
+	if len(initrdList) > 0 {
+		initrd, err := os.CreateTemp(".", "initrd")
+		if err != nil {
+			log.Fatalf("Failed to create temporary initrd: %v", err)
+		}
+		defer os.Remove(initrd.Name())
+		for _, initrdPath := range initrdList {
+			initrdSrc, err := os.Open(initrdPath)
+			if err != nil {
+				log.Fatalf("Failed to open initrd file: %v", err)
+			}
+			if _, err := io.Copy(initrd, initrdSrc); err != nil {
+				initrdSrc.Close()
+				log.Fatalf("Failed concatinating initrd: %v", err)
+			}
+			initrdSrc.Close()
+		}
+		initrdPath = initrd.Name()
+	}
+	sec := sections["initrd"]
+	sec.file = &initrdPath
+	sections["initrd"] = sec
+
 	// Execute objcopy
 	var args []string
 	for name, c := range sections {