diff --git a/filesystem/Android.bp b/filesystem/Android.bp
index 926df6e..9994241 100644
--- a/filesystem/Android.bp
+++ b/filesystem/Android.bp
@@ -7,6 +7,7 @@
         "soong-android",
     ],
     srcs: [
+        "bootimg.go",
         "filesystem.go",
     ],
     testSrcs: [
diff --git a/filesystem/bootimg.go b/filesystem/bootimg.go
new file mode 100644
index 0000000..4bc1823
--- /dev/null
+++ b/filesystem/bootimg.go
@@ -0,0 +1,222 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package filesystem
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/google/blueprint"
+	"github.com/google/blueprint/proptools"
+
+	"android/soong/android"
+)
+
+func init() {
+	android.RegisterModuleType("bootimg", bootimgFactory)
+}
+
+type bootimg struct {
+	android.ModuleBase
+
+	properties bootimgProperties
+
+	output     android.OutputPath
+	installDir android.InstallPath
+}
+
+type bootimgProperties struct {
+	// Path to the linux kernel prebuilt file
+	Kernel_prebuilt *string `android:"arch_variant,path"`
+
+	// Filesystem module that is used as ramdisk
+	Ramdisk_module *string
+
+	// Path to the device tree blob (DTB) prebuilt file to add to this boot image
+	Dtb_prebuilt *string `android:"arch_variant,path"`
+
+	// Header version number. Must be set to one of the version numbers that are currently
+	// supported. Refer to
+	// https://source.android.com/devices/bootloader/boot-image-header
+	Header_version *string
+
+	// Determines if this image is for the vendor_boot partition. Default is false. Refer to
+	// https://source.android.com/devices/bootloader/partitions/vendor-boot-partitions
+	Vendor_boot *bool
+
+	// Optional kernel commandline
+	Cmdline *string
+
+	// When set to true, sign the image with avbtool. Default is false.
+	Use_avb *bool
+
+	// Name of the partition stored in vbmeta desc. Defaults to the name of this module.
+	Partition_name *string
+
+	// Path to the private key that avbtool will use to sign this filesystem image.
+	// TODO(jiyong): allow apex_key to be specified here
+	Avb_private_key *string `android:"path"`
+
+	// Hash and signing algorithm for avbtool. Default is SHA256_RSA4096.
+	Avb_algorithm *string
+}
+
+// bootimg is the image for the boot partition. It consists of header, kernel, ramdisk, and dtb.
+func bootimgFactory() android.Module {
+	module := &bootimg{}
+	module.AddProperties(&module.properties)
+	android.InitAndroidArchModule(module, android.DeviceSupported, android.MultilibFirst)
+	return module
+}
+
+type bootimgDep struct {
+	blueprint.BaseDependencyTag
+	kind string
+}
+
+var bootimgRamdiskDep = bootimgDep{kind: "ramdisk"}
+
+func (b *bootimg) DepsMutator(ctx android.BottomUpMutatorContext) {
+	ramdisk := proptools.String(b.properties.Ramdisk_module)
+	if ramdisk != "" {
+		ctx.AddDependency(ctx.Module(), bootimgRamdiskDep, ramdisk)
+	}
+}
+
+func (b *bootimg) installFileName() string {
+	return b.BaseModuleName() + ".img"
+}
+
+func (b *bootimg) partitionName() string {
+	return proptools.StringDefault(b.properties.Partition_name, b.BaseModuleName())
+}
+
+func (b *bootimg) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	var unsignedOutput android.OutputPath
+	if proptools.Bool(b.properties.Vendor_boot) {
+		unsignedOutput = b.buildVendorBootImage(ctx)
+	} else {
+		// TODO(jiyong): fix this
+		ctx.PropertyErrorf("vendor_boot", "only vendor_boot:true is supported")
+	}
+
+	if proptools.Bool(b.properties.Use_avb) {
+		b.output = b.signImage(ctx, unsignedOutput)
+	} else {
+		b.output = unsignedOutput
+	}
+
+	b.installDir = android.PathForModuleInstall(ctx, "etc")
+	ctx.InstallFile(b.installDir, b.installFileName(), b.output)
+}
+
+func (b *bootimg) buildVendorBootImage(ctx android.ModuleContext) android.OutputPath {
+	output := android.PathForModuleOut(ctx, "unsigned.img").OutputPath
+	builder := android.NewRuleBuilder(pctx, ctx)
+	cmd := builder.Command().BuiltTool("mkbootimg")
+
+	kernel := android.OptionalPathForModuleSrc(ctx, b.properties.Kernel_prebuilt)
+	if kernel.Valid() {
+		ctx.PropertyErrorf("kernel_prebuilt", "vendor_boot partition can't have kernel")
+		return output
+	}
+
+	dtbName := proptools.String(b.properties.Dtb_prebuilt)
+	if dtbName == "" {
+		ctx.PropertyErrorf("dtb_prebuilt", "must be set")
+		return output
+	}
+	dtb := android.PathForModuleSrc(ctx, dtbName)
+	cmd.FlagWithInput("--dtb ", dtb)
+
+	cmdline := proptools.String(b.properties.Cmdline)
+	if cmdline != "" {
+		cmd.FlagWithArg("--vendor_cmdline ", "\""+cmdline+"\"")
+	}
+
+	headerVersion := proptools.String(b.properties.Header_version)
+	if headerVersion == "" {
+		ctx.PropertyErrorf("header_version", "must be set")
+		return output
+	}
+	verNum, err := strconv.Atoi(headerVersion)
+	if err != nil {
+		ctx.PropertyErrorf("header_version", "%q is not a number", headerVersion)
+		return output
+	}
+	if verNum < 3 {
+		ctx.PropertyErrorf("header_version", "must be 3 or higher for vendor_boot")
+		return output
+	}
+	cmd.FlagWithArg("--header_version ", headerVersion)
+
+	ramdiskName := proptools.String(b.properties.Ramdisk_module)
+	if ramdiskName == "" {
+		ctx.PropertyErrorf("ramdisk_module", "must be set")
+		return output
+	}
+	ramdisk := ctx.GetDirectDepWithTag(ramdiskName, bootimgRamdiskDep)
+	if filesystem, ok := ramdisk.(*filesystem); ok {
+		cmd.FlagWithInput("--vendor_ramdisk ", filesystem.OutputPath())
+	} else {
+		ctx.PropertyErrorf("ramdisk", "%q is not android_filesystem module", ramdisk.Name())
+		return output
+	}
+
+	cmd.FlagWithOutput("--vendor_boot ", output)
+
+	builder.Build("build_vendor_bootimg", fmt.Sprintf("Creating %s", b.BaseModuleName()))
+	return output
+}
+
+func (b *bootimg) signImage(ctx android.ModuleContext, unsignedImage android.OutputPath) android.OutputPath {
+	signedImage := android.PathForModuleOut(ctx, "signed.img").OutputPath
+	key := android.PathForModuleSrc(ctx, proptools.String(b.properties.Avb_private_key))
+
+	builder := android.NewRuleBuilder(pctx, ctx)
+	builder.Command().Text("cp").Input(unsignedImage).Output(signedImage)
+	builder.Command().
+		BuiltTool("avbtool").
+		Flag("add_hash_footer").
+		FlagWithArg("--partition_name ", b.partitionName()).
+		FlagWithInput("--key ", key).
+		FlagWithOutput("--image ", signedImage)
+
+	builder.Build("sign_bootimg", fmt.Sprintf("Signing %s", b.BaseModuleName()))
+
+	return signedImage
+}
+
+var _ android.AndroidMkEntriesProvider = (*bootimg)(nil)
+
+// Implements android.AndroidMkEntriesProvider
+func (b *bootimg) AndroidMkEntries() []android.AndroidMkEntries {
+	return []android.AndroidMkEntries{android.AndroidMkEntries{
+		Class:      "ETC",
+		OutputFile: android.OptionalPathForPath(b.output),
+		ExtraEntries: []android.AndroidMkExtraEntriesFunc{
+			func(entries *android.AndroidMkEntries) {
+				entries.SetString("LOCAL_MODULE_PATH", b.installDir.ToMakePath().String())
+				entries.SetString("LOCAL_INSTALLED_MODULE_STEM", b.installFileName())
+			},
+		},
+	}}
+}
+
+var _ Filesystem = (*bootimg)(nil)
+
+func (b *bootimg) OutputPath() android.Path {
+	return b.output
+}