diff --git a/fs_mgr/TEST_MAPPING b/fs_mgr/TEST_MAPPING
index db27cf0..d357e45 100644
--- a/fs_mgr/TEST_MAPPING
+++ b/fs_mgr/TEST_MAPPING
@@ -24,9 +24,8 @@
     {
       "name": "vab_legacy_tests"
     },
-    {
-      "name": "vabc_legacy_tests"
-    },
+    // TODO: b/279009697
+    //{"name": "vabc_legacy_tests"},
     {
       "name": "cow_api_test"
     }
@@ -43,9 +42,8 @@
     },
     {
       "name": "vab_legacy_tests"
-    },
-    {
-      "name": "vabc_legacy_tests"
     }
+    // TODO: b/279009697
+    //{"name": "vabc_legacy_tests"}
   ]
 }
diff --git a/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd.cpp b/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd.cpp
index 1fa4144..efa43b7 100644
--- a/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd.cpp
@@ -509,10 +509,8 @@
             // in the file.
             //===========================================================
             uint64_t block_source = cow_op->source;
-            uint64_t block_offset = 0;
             if (prev_id.has_value()) {
-                if (dest_blocks.count(cow_op->new_block) || source_blocks.count(block_source) ||
-                    (block_offset > 0 && source_blocks.count(block_source + 1))) {
+                if (dest_blocks.count(cow_op->new_block) || source_blocks.count(block_source)) {
                     break;
                 }
             }
@@ -520,9 +518,6 @@
             pending_ordered_ops -= 1;
             vec.push_back(cow_op);
             dest_blocks.insert(block_source);
-            if (block_offset > 0) {
-                dest_blocks.insert(block_source + 1);
-            }
             source_blocks.insert(cow_op->new_block);
             prev_id = cow_op->new_block;
             cowop_rm_iter->Next();
diff --git a/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd_readahead.cpp b/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd_readahead.cpp
index 01123f8..a32c2bf 100644
--- a/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd_readahead.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/dm-snapshot-merge/snapuserd_readahead.cpp
@@ -173,16 +173,11 @@
 
 void ReadAheadThread::CheckOverlap(const CowOperation* cow_op) {
     uint64_t source_block = cow_op->source;
-    uint64_t source_offset = 0;
-    if (dest_blocks_.count(cow_op->new_block) || source_blocks_.count(source_block) ||
-        (source_offset > 0 && source_blocks_.count(source_block + 1))) {
+    if (dest_blocks_.count(cow_op->new_block) || source_blocks_.count(source_block)) {
         overlap_ = true;
     }
 
     dest_blocks_.insert(source_block);
-    if (source_offset > 0) {
-        dest_blocks_.insert(source_block + 1);
-    }
     source_blocks_.insert(cow_op->new_block);
 }
 
diff --git a/init/init_test.cpp b/init/init_test.cpp
index 0fc3ffc..7e8513b 100644
--- a/init/init_test.cpp
+++ b/init/init_test.cpp
@@ -180,9 +180,11 @@
     std::string init_script = R"init(
 service A something
     class first
+    user nobody
 
 service A something
     class second
+    user nobody
     override
 
 )init";
@@ -610,6 +612,31 @@
     EXPECT_EQ(2, num_executed);
 }
 
+TEST(init, RejectsNoUserStartingInV) {
+    std::string init_script =
+            R"init(
+service A something
+    class first
+)init";
+
+    TemporaryFile tf;
+    ASSERT_TRUE(tf.fd != -1);
+    ASSERT_TRUE(android::base::WriteStringToFd(init_script, tf.fd));
+
+    ServiceList service_list;
+    Parser parser;
+    parser.AddSectionParser("service",
+                            std::make_unique<ServiceParser>(&service_list, nullptr, std::nullopt));
+
+    ASSERT_TRUE(parser.ParseConfig(tf.path));
+
+    if (GetIntProperty("ro.vendor.api_level", 0) > __ANDROID_API_U__) {
+        ASSERT_EQ(1u, parser.parse_error_count());
+    } else {
+        ASSERT_EQ(0u, parser.parse_error_count());
+    }
+}
+
 TEST(init, RejectsCriticalAndOneshotService) {
     if (GetIntProperty("ro.product.first_api_level", 10000) < 30) {
         GTEST_SKIP() << "Test only valid for devices launching with R or later";
@@ -619,6 +646,7 @@
             R"init(
 service A something
   class first
+  user root
   critical
   oneshot
 )init";
diff --git a/init/service_parser.cpp b/init/service_parser.cpp
index d89664c..d46e1f7 100644
--- a/init/service_parser.cpp
+++ b/init/service_parser.cpp
@@ -25,6 +25,7 @@
 
 #include <android-base/logging.h>
 #include <android-base/parseint.h>
+#include <android-base/properties.h>
 #include <android-base/strings.h>
 #include <hidl-util/FQName.h>
 #include <processgroup/processgroup.h>
@@ -678,8 +679,13 @@
     }
 
     if (service_->proc_attr_.parsed_uid == std::nullopt) {
-        LOG(WARNING) << "No user specified for service '" << service_->name()
-                     << "'. Defaults to root.";
+        if (android::base::GetIntProperty("ro.vendor.api_level", 0) > __ANDROID_API_U__) {
+            return Error() << "No user specified for service '" << service_->name()
+                           << "'. Defaults to root.";
+        } else {
+            LOG(WARNING) << "No user specified for service '" << service_->name()
+                         << "'. Defaults to root.";
+        }
     }
 
     if (interface_inheritance_hierarchy_) {
diff --git a/rootdir/init.usb.rc b/rootdir/init.usb.rc
index 0730cce..dde784e 100644
--- a/rootdir/init.usb.rc
+++ b/rootdir/init.usb.rc
@@ -18,6 +18,7 @@
     disabled
     updatable
     seclabel u:r:adbd:s0
+    user root
 
 on property:vendor.sys.usb.adb.disabled=*
     setprop sys.usb.adb.disabled ${vendor.sys.usb.adb.disabled}