Move ramdisk to the new init_boot partition

The updated u-bootloader demands it.

Bug: N/A
Test: atest MicrodroidHostTestCases
Change-Id: I7024f20eb9d7c637437236f844a0c0f45db41bf1

apex/Android.bp

@@ -5,6 +5,7 @@ package {
 microdroid_filesystem_images = [
     "microdroid_super",
     "microdroid_boot-5.10",
+    "microdroid_init_boot",
     "microdroid_vendor_boot-5.10",
     "microdroid_vbmeta",
     "microdroid_vbmeta_bootconfig",

apex/sign_virt_apex.py

@@ -282,6 +282,8 @@ def SignVirtApex(args):
     boot_img = os.path.join(input_dir, 'etc', 'fs', 'microdroid_boot-5.10.img')
     vendor_boot_img = os.path.join(
         input_dir, 'etc', 'fs', 'microdroid_vendor_boot-5.10.img')
+    init_boot_img = os.path.join(
+        input_dir, 'etc', 'fs', 'microdroid_init_boot.img')
     super_img = os.path.join(input_dir, 'etc', 'fs', 'microdroid_super.img')
     vbmeta_img = os.path.join(input_dir, 'etc', 'fs', 'microdroid_vbmeta.img')
     vbmeta_bootconfig_img = os.path.join(
@@ -297,10 +299,11 @@ def SignVirtApex(args):
     # while it's okay to use different keys for other image files.
     ReplaceBootloaderPubkey(args, key, bootloader, bootloader_pubkey)
 
-    # re-sign bootloader, boot.img, vendor_boot.img
+    # re-sign bootloader, boot.img, vendor_boot.img, and init_boot.img
     AddHashFooter(args, key, bootloader)
     AddHashFooter(args, key, boot_img)
     AddHashFooter(args, key, vendor_boot_img)
+    AddHashFooter(args, key, init_boot_img)
 
     # re-sign super.img
     with TempDirectory() as work_dir:
@@ -320,12 +323,12 @@ def SignVirtApex(args):
         # re-pack super.img
         MakeSuperImage(args, partitions, super_img)
 
-        # re-generate vbmeta from re-signed {boot, vendor_boot, system_a, vendor_a}.img
+        # re-generate vbmeta from re-signed {boot, vendor_boot, init_boot, system_a, vendor_a}.img
         # Ideally, making VBmeta should be done out of TempDirectory block. But doing it here
         # to avoid unpacking re-signed super.img for system/vendor images which are available
         # in this block.
         MakeVbmetaImage(args, key, vbmeta_img, images=[
-                        boot_img, vendor_boot_img, system_a_img, vendor_a_img])
+                        boot_img, vendor_boot_img, init_boot_img, system_a_img, vendor_a_img])
 
     # Re-sign bootconfigs with the same key
     bootconfig_sign_key = key

microdroid/Android.bp

@@ -221,7 +221,6 @@ microdroid_boot_cmdline = [
 
 bootimg {
     name: "microdroid_boot-5.10",
-    ramdisk_module: "microdroid_ramdisk-5.10",
     // We don't have kernel for arm and x86. But Soong demands one when it builds for
     // arm or x86 target. Satisfy that by providing an empty file as the kernel.
     kernel_prebuilt: "empty_kernel",
@@ -251,6 +250,16 @@ bootimg {
     avb_private_key: ":microdroid_sign_key",
 }
 
+bootimg {
+    name: "microdroid_init_boot",
+    ramdisk_module: "microdroid_ramdisk-5.10",
+    kernel_prebuilt: "empty_kernel",
+    header_version: "4",
+    partition_name: "init_boot",
+    use_avb: true,
+    avb_private_key: ":microdroid_sign_key",
+}
+
 android_filesystem {
     name: "microdroid_ramdisk-5.10",
     deps: [
@@ -551,6 +560,7 @@ vbmeta {
         "microdroid_vendor_boot-5.10",
         "microdroid",
         "microdroid_boot-5.10",
+        "microdroid_init_boot",
     ],
 }
 

microdroid/microdroid.json

@@ -7,6 +7,10 @@
           "label": "boot_a",
           "path": "/apex/com.android.virt/etc/fs/microdroid_boot-5.10.img"
         },
+        {
+          "label": "init_boot_a",
+          "path": "/apex/com.android.virt/etc/fs/microdroid_init_boot.img"
+        },
         {
           "label": "vendor_boot_a",
           "path": "/apex/com.android.virt/etc/fs/microdroid_vendor_boot-5.10.img"