diff --git a/pvmfw/Android.bp b/pvmfw/Android.bp
index c9909e6..35fd52f 100644
--- a/pvmfw/Android.bp
+++ b/pvmfw/Android.bp
@@ -7,7 +7,6 @@
     crate_name: "pvmfw",
     defaults: ["vmbase_ffi_defaults"],
     srcs: ["src/main.rs"],
-    edition: "2021",
     // Require unsafe blocks for inside unsafe functions.
     flags: ["-Dunsafe_op_in_unsafe_fn"],
     features: [
@@ -83,7 +82,6 @@
     // partition image. This is just to package the unstripped file into the
     // symbols zip file for debugging purpose.
     installable: true,
-    native_coverage: false,
 }
 
 raw_binary {
@@ -135,8 +133,7 @@
 
 rust_library_rlib {
     name: "libpvmfw_embedded_key",
-    defaults: ["vmbase_ffi_defaults"],
-    prefer_rlib: true,
+    defaults: ["vmbase_rlib_defaults"],
     srcs: [":pvmfw_embedded_key_rs"],
     crate_name: "pvmfw_embedded_key",
     apex_available: ["com.android.virt"],
@@ -193,8 +190,7 @@
 
 rust_library_rlib {
     name: "libpvmfw_fdt_template",
-    defaults: ["vmbase_ffi_defaults"],
-    prefer_rlib: true,
+    defaults: ["vmbase_rlib_defaults"],
     srcs: [":pvmfw_fdt_template_rs"],
     crate_name: "pvmfw_fdt_template",
 }
diff --git a/rialto/Android.bp b/rialto/Android.bp
index 59f8ba2..60f36fc 100644
--- a/rialto/Android.bp
+++ b/rialto/Android.bp
@@ -6,7 +6,6 @@
     name: "librialto",
     crate_name: "rialto",
     srcs: ["src/main.rs"],
-    edition: "2021",
     defaults: ["vmbase_ffi_defaults"],
     rustlibs: [
         "libaarch64_paging",
@@ -29,7 +28,6 @@
     ],
     static_libs: [
         "librialto",
-        "libvmbase_entry",
     ],
     linker_scripts: [
         "image.ld",
diff --git a/vmbase/Android.bp b/vmbase/Android.bp
index ac010b9..d7648d6 100644
--- a/vmbase/Android.bp
+++ b/vmbase/Android.bp
@@ -2,11 +2,28 @@
     default_applicable_licenses: ["Android-Apache-2.0"],
 }
 
+// The hierarchy of Soong modules to produce a vmbase-based binary is
+//
+// 0. rlibs may be used to provide high-level code (see "vmbase_rlib_defaults");
+// 1. rust_ffi_static packages low-level Rust code and any rlib into a static
+//    library (see "vmbase_ffi_defaults") that cc_binary supports;
+// 2. cc_library_static may be used for extra C code (see "vmbase_cc_defaults");
+// 3. cc_binary produces an ELF from the (single) Rust-wrapping static library,
+//    optional extra C libraries, and linker script (see "vmbase_elf_defaults");
+// 4. raw_binary strips the ELF into an image that can be loaded to memory;
+
+// Used by intermediate rust_library_rlib for vmbase-based binaries.
 rust_defaults {
-    name: "vmbase_rust_defaults",
+    name: "vmbase_rlib_defaults",
     edition: "2021",
+    prefer_rlib: true,
     host_supported: false,
     enabled: false,
+    no_stdlibs: true,
+    stdlibs: [
+        "libcompiler_builtins.rust_sysroot",
+        "libcore.rust_sysroot",
+    ],
     target: {
         android_arm64: {
             enabled: true,
@@ -14,19 +31,17 @@
     },
 }
 
+// Used by the "top-level" rust_ffi_static of vmbase-based binaries.
 rust_defaults {
     name: "vmbase_ffi_defaults",
-    defaults: ["vmbase_rust_defaults"],
-    no_stdlibs: true,
-    stdlibs: [
-        "libcompiler_builtins.rust_sysroot",
-        "libcore.rust_sysroot",
-    ],
+    defaults: ["vmbase_rlib_defaults"],
 }
 
+// Used by extra cc_library_static linked into the final ELF.
 cc_defaults {
     name: "vmbase_cc_defaults",
     nocrt: true,
+    no_libcrt: true,
     system_shared_libs: [],
     stl: "none",
     installable: false,
@@ -39,8 +54,10 @@
     sanitize: {
         hwaddress: false,
     },
+    native_coverage: false,
 }
 
+// Used by cc_binary when producing the ELF of a vmbase-based binary.
 cc_defaults {
     name: "vmbase_elf_defaults",
     defaults: ["vmbase_cc_defaults"],
@@ -48,18 +65,11 @@
     static_libs: [
         "libvmbase_entry",
     ],
-    installable: false,
-    enabled: false,
-    target: {
-        android_arm64: {
-            enabled: true,
-        },
-    },
 }
 
 rust_library_rlib {
     name: "libvmbase",
-    defaults: ["vmbase_rust_defaults"],
+    defaults: ["vmbase_rlib_defaults"],
     crate_name: "vmbase",
     srcs: ["src/lib.rs"],
     rustlibs: [
@@ -76,7 +86,6 @@
         "libvirtio_drivers",
         "libzeroize_nostd",
     ],
-    no_stdlibs: true,
     whole_static_libs: [
         "librust_baremetal",
     ],
@@ -94,7 +103,6 @@
         "exceptions.S",
         "exceptions_panic.S",
     ],
-    no_libcrt: true,
     apex_available: ["com.android.virt"],
 }
 
diff --git a/vmbase/example/Android.bp b/vmbase/example/Android.bp
index dc9a090..32854c2 100644
--- a/vmbase/example/Android.bp
+++ b/vmbase/example/Android.bp
@@ -7,7 +7,6 @@
     defaults: ["vmbase_ffi_defaults"],
     crate_name: "vmbase_example",
     srcs: ["src/main.rs"],
-    edition: "2021",
     rustlibs: [
         "libaarch64_paging",
         "libbuddy_system_allocator",