diff --git a/tests/hostside/Android.bp b/tests/hostside/Android.bp
index bfe215d..d8c9871 100644
--- a/tests/hostside/Android.bp
+++ b/tests/hostside/Android.bp
@@ -12,6 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+kernel_version = "5.4"
+
+kernel_target_stem = ":kernel_prebuilts-" + kernel_version
+vendor_ramdisk_target_stem = ":cf_prebuilts_initramfs-" + kernel_version
+
 // Ramdisk containing /init and test binaries/resources needed inside guest.
 genrule {
     name: "virt_hostside_tests_initramfs_base",
@@ -28,3 +33,27 @@
         "$(genDir)/root/init " +
         "&& $(location mkbootfs) $(genDir)/root | $(location lz4) -fq - $(out)",
 }
+
+// Default rule for producing a combined base + vendor ramdisk.
+genrule_defaults {
+    name: "virt_hostside_tests_initramfs_concat",
+    srcs: [":virt_hostside_tests_initramfs_base"],
+    tools: ["lz4"],
+    cmd: "cat $(in) | $(location lz4) -dfq - $(out)",
+}
+
+// Combined base + vendor ramdisk for arm64.
+genrule {
+    name: "virt_hostside_tests_initramfs-arm64",
+    defaults: ["virt_hostside_tests_initramfs_concat"],
+    srcs: [vendor_ramdisk_target_stem + "-arm64"],
+    out: ["virt_hostside_tests_initramfs-arm64"],
+}
+
+// Combined base + vendor ramdisk for x86_64.
+genrule {
+    name: "virt_hostside_tests_initramfs-x86_64",
+    defaults: ["virt_hostside_tests_initramfs_concat"],
+    srcs: [vendor_ramdisk_target_stem + "-x86_64"],
+    out: ["virt_hostside_tests_initramfs-x86_64"],
+}