Revert "Revert "Move ramdisk to the new init_boot partition""

This reverts commit 3c76abb8ea0c3c95e53a38c13c9e29791e0f10ae.

Reason for revert: Presubmits should now pass with fixed u-boot prebuilts

Change-Id: I5f60c10640cd19ee2ed4b874a077c1596a53e612
diff --git a/apex/Android.bp b/apex/Android.bp
index f1eeed9..25cd480 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -5,6 +5,7 @@
 microdroid_filesystem_images = [
     "microdroid_super",
     "microdroid_boot-5.10",
+    "microdroid_init_boot",
     "microdroid_vendor_boot-5.10",
     "microdroid_vbmeta",
     "microdroid_vbmeta_bootconfig",
diff --git a/apex/sign_virt_apex.py b/apex/sign_virt_apex.py
index 153b5dd..9a0fe1a 100644
--- a/apex/sign_virt_apex.py
+++ b/apex/sign_virt_apex.py
@@ -282,6 +282,8 @@
     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 @@
     # 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 @@
         # 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