diff --git a/fs_mgr/fs_mgr_overlayfs.cpp b/fs_mgr/fs_mgr_overlayfs.cpp
index 6942d0c..07eaf58 100644
--- a/fs_mgr/fs_mgr_overlayfs.cpp
+++ b/fs_mgr/fs_mgr_overlayfs.cpp
@@ -642,6 +642,10 @@
     if (ret) {
         PERROR << "__mount(target=" << mount_point
                << ",flag=" << (shared_flag ? "MS_SHARED" : "MS_PRIVATE") << ")=" << ret;
+        // If "/system" doesn't look like a mountpoint, retry with "/".
+        if (errno == EINVAL && mount_point == "/system") {
+            return fs_mgr_overlayfs_set_shared_mount("/", shared_flag);
+        }
         return false;
     }
     return true;
diff --git a/fs_mgr/libfiemap/image_test.cpp b/fs_mgr/libfiemap/image_test.cpp
index 7472949..fb104b7 100644
--- a/fs_mgr/libfiemap/image_test.cpp
+++ b/fs_mgr/libfiemap/image_test.cpp
@@ -14,11 +14,13 @@
 // limitations under the License.
 //
 
+#include <inttypes.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mount.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/vfs.h>
 
 #include <chrono>
 #include <iostream>
@@ -26,12 +28,14 @@
 
 #include <android-base/file.h>
 #include <android-base/properties.h>
+#include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <ext4_utils/ext4_utils.h>
 #include <fs_mgr/file_wait.h>
 #include <gtest/gtest.h>
 #include <libdm/dm.h>
+#include <libdm/loop_control.h>
 #include <libfiemap/image_manager.h>
 
 #include "utility.h"
@@ -46,7 +50,7 @@
 using android::fs_mgr::WaitForFile;
 
 static std::string gDataPath;
-static std::string gDataMountPath;
+static std::string gTestDir;
 static constexpr char kMetadataPath[] = "/metadata/gsi/test";
 
 static constexpr uint64_t kTestImageSize = 1024 * 1024;
@@ -178,6 +182,119 @@
 
 INSTANTIATE_TEST_SUITE_P(IsSubdirTest, IsSubdirTest, ::testing::ValuesIn(IsSubdirTestValues()));
 
+// This allows test cases for filesystems with larger than 4KiB alignment.
+// It creates a loop device, formats it with a FAT filesystem, and then
+// creates an ImageManager so backing images can be created on that filesystem.
+class VfatTest : public ::testing::Test {
+  protected:
+    // 64MB Filesystem and 32k block size by default
+    static constexpr uint64_t kBlockSize = 32768;
+    static constexpr uint64_t kFilesystemSize = 64 * 1024 * 1024;
+
+    void SetUp() override {
+        const ::testing::TestInfo* tinfo = ::testing::UnitTest::GetInstance()->current_test_info();
+        base_name_ = tinfo->name();
+
+        fs_path_ = gTestDir + "/vfat.img";
+        uint64_t count = kFilesystemSize / kBlockSize;
+        std::string dd_cmd =
+                ::android::base::StringPrintf("/system/bin/dd if=/dev/zero of=%s bs=%" PRIu64
+                                              " count=%" PRIu64 " > /dev/null 2>&1",
+                                              fs_path_.c_str(), kBlockSize, count);
+        // create mount point
+        mntpoint_ = std::string(getenv("TMPDIR")) + "/fiemap_mnt";
+        if (mkdir(mntpoint_.c_str(), S_IRWXU) < 0) {
+            ASSERT_EQ(errno, EEXIST) << strerror(errno);
+        }
+
+        // create file for the file system
+        int ret = system(dd_cmd.c_str());
+        ASSERT_EQ(ret, 0);
+
+        // Get and attach a loop device to the filesystem we created
+        loop_device_.emplace(fs_path_, 10s);
+        ASSERT_TRUE(loop_device_->valid());
+
+        // create file system
+        uint64_t sectors = kFilesystemSize / 512;
+        std::string mkfs_cmd =
+                ::android::base::StringPrintf("/system/bin/newfs_msdos -A -O Android -s %" PRIu64
+                                              " -b %" PRIu64 " %s > /dev/null 2>&1",
+                                              sectors, kBlockSize, loop_device_->device().c_str());
+        ret = system(mkfs_cmd.c_str());
+        ASSERT_EQ(ret, 0);
+
+        // Create a wrapping DM device to prevent gsid taking the loopback path.
+        auto& dm = DeviceMapper::Instance();
+        DmTable table;
+        table.Emplace<DmTargetLinear>(0, kFilesystemSize / 512, loop_device_->device(), 0);
+
+        dm_name_ = android::base::Basename(loop_device_->device()) + "-wrapper";
+        ASSERT_TRUE(dm.CreateDevice(dm_name_, table, &dm_path_, 10s));
+
+        // mount the file system
+        ASSERT_EQ(mount(dm_path_.c_str(), mntpoint_.c_str(), "vfat", 0, nullptr), 0)
+                << strerror(errno);
+    }
+
+    void TearDown() override {
+        // Clear up anything backed on the temporary FS.
+        if (manager_) {
+            manager_->UnmapImageIfExists(base_name_);
+            manager_->DeleteBackingImage(base_name_);
+        }
+
+        // Unmount temporary FS.
+        if (umount(mntpoint_.c_str()) < 0) {
+            ASSERT_EQ(errno, EINVAL) << strerror(errno);
+        }
+
+        // Destroy the dm wrapper.
+        auto& dm = DeviceMapper::Instance();
+        ASSERT_TRUE(dm.DeleteDeviceIfExists(dm_name_));
+
+        // Destroy the loop device.
+        loop_device_ = {};
+
+        // Destroy the temporary FS.
+        if (rmdir(mntpoint_.c_str()) < 0) {
+            ASSERT_EQ(errno, ENOENT) << strerror(errno);
+        }
+        if (unlink(fs_path_.c_str()) < 0) {
+            ASSERT_EQ(errno, ENOENT) << strerror(errno);
+        }
+    }
+
+    std::string base_name_;
+    std::string mntpoint_;
+    std::string fs_path_;
+    std::optional<LoopDevice> loop_device_;
+    std::string dm_name_;
+    std::string dm_path_;
+    std::unique_ptr<ImageManager> manager_;
+};
+
+// The actual size of the block device should be the requested size. For
+// example, a 16KB image should be mapped as a 16KB device, even if the
+// underlying filesystem requires 32KB to be fallocated.
+TEST_F(VfatTest, DeviceIsRequestedSize) {
+    manager_ = ImageManager::Open(kMetadataPath, mntpoint_);
+    ASSERT_NE(manager_, nullptr);
+
+    manager_->set_partition_opener(std::make_unique<TestPartitionOpener>());
+
+    // Create something not aligned to the backing fs block size.
+    constexpr uint64_t kTestSize = (kBlockSize * 64) - (kBlockSize / 2);
+    ASSERT_TRUE(manager_->CreateBackingImage(base_name_, kTestSize, false, nullptr));
+
+    std::string path;
+    ASSERT_TRUE(manager_->MapImageDevice(base_name_, 10s, &path));
+
+    unique_fd fd(open(path.c_str(), O_RDONLY | O_CLOEXEC));
+    ASSERT_GE(fd, 0);
+    ASSERT_EQ(get_block_device_size(fd.get()), kTestSize);
+}
+
 }  // namespace
 
 bool Mkdir(const std::string& path) {
@@ -194,13 +311,27 @@
     if (argc >= 2) {
         gDataPath = argv[1];
     } else {
-        gDataPath = "/data/gsi/test";
+        gDataPath = "/data/local/tmp";
     }
-    gDataMountPath = gDataPath + "/mnt"s;
 
-    if (!Mkdir(gDataPath) || !Mkdir(kMetadataPath) || !Mkdir(gDataMountPath) ||
-        !Mkdir(kMetadataPath + "/mnt"s)) {
+    if (!Mkdir(gDataPath) || !Mkdir(kMetadataPath) || !Mkdir(kMetadataPath + "/mnt"s)) {
         return 1;
     }
-    return RUN_ALL_TESTS();
+
+    std::string tempdir = gDataPath + "/XXXXXX";
+    if (!mkdtemp(tempdir.data())) {
+        std::cerr << "unable to create tempdir on " << tempdir << "\n";
+        exit(EXIT_FAILURE);
+    }
+    if (!android::base::Realpath(tempdir, &gTestDir)) {
+        std::cerr << "unable to find realpath for " << tempdir;
+        exit(EXIT_FAILURE);
+    }
+
+    auto rv = RUN_ALL_TESTS();
+
+    std::string cmd = "rm -rf " + gTestDir;
+    system(cmd.c_str());
+
+    return rv;
 }
diff --git a/init/init.cpp b/init/init.cpp
index 535033d..5f516b7 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -347,8 +347,8 @@
     }
 #endif  // RECOVERY
     parser.AddSectionParser("service",
-                            std::make_unique<ServiceParser>(&service_list, subcontext, std::nullopt,
-                                                            /*from_apex=*/true));
+                            std::make_unique<ServiceParser>(&service_list, subcontext,
+                            std::nullopt));
     parser.AddSectionParser("on", std::make_unique<ActionParser>(&action_manager, subcontext));
 
     return parser;
diff --git a/init/mount_namespace.cpp b/init/mount_namespace.cpp
index bce1cc3..fead371 100644
--- a/init/mount_namespace.cpp
+++ b/init/mount_namespace.cpp
@@ -190,15 +190,33 @@
     return success;
 }
 
+// Switch the mount namespace of the current process from bootstrap to default OR from default to
+// bootstrap. If the current mount namespace is neither bootstrap nor default, keep it that way.
 Result<void> SwitchToMountNamespaceIfNeeded(MountNamespace target_mount_namespace) {
     if (IsRecoveryMode() || !IsApexUpdatable()) {
         // we don't have multiple namespaces in recovery mode or if apex is not updatable
         return {};
     }
-    const auto& ns_id = target_mount_namespace == NS_BOOTSTRAP ? bootstrap_ns_id : default_ns_id;
+
+    const std::string current_namespace_id = GetMountNamespaceId();
+    MountNamespace current_mount_namespace;
+    if (current_namespace_id == bootstrap_ns_id) {
+        current_mount_namespace = NS_BOOTSTRAP;
+    } else if (current_namespace_id == default_ns_id) {
+        current_mount_namespace = NS_DEFAULT;
+    } else {
+        // services with `namespace mnt` start in its own mount namespace. So we need to keep it.
+        return {};
+    }
+
+    // We're already in the target mount namespace.
+    if (current_mount_namespace == target_mount_namespace) {
+        return {};
+    }
+
     const auto& ns_fd = target_mount_namespace == NS_BOOTSTRAP ? bootstrap_ns_fd : default_ns_fd;
     const auto& ns_name = target_mount_namespace == NS_BOOTSTRAP ? "bootstrap" : "default";
-    if (ns_id != GetMountNamespaceId() && ns_fd.get() != -1) {
+    if (ns_fd.get() != -1) {
         if (setns(ns_fd.get(), CLONE_NEWNS) == -1) {
             return ErrnoError() << "Failed to switch to " << ns_name << " mount namespace.";
         }
diff --git a/init/service.cpp b/init/service.cpp
index 8c4ee93..730b6b6 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -130,13 +130,13 @@
 std::chrono::time_point<std::chrono::steady_clock> Service::exec_service_started_;
 
 Service::Service(const std::string& name, Subcontext* subcontext_for_restart_commands,
-                 const std::vector<std::string>& args, bool from_apex)
-    : Service(name, 0, 0, 0, {}, 0, "", subcontext_for_restart_commands, args, from_apex) {}
+                 const std::string& filename, const std::vector<std::string>& args)
+    : Service(name, 0, 0, 0, {}, 0, "", subcontext_for_restart_commands, filename, args) {}
 
 Service::Service(const std::string& name, unsigned flags, uid_t uid, gid_t gid,
                  const std::vector<gid_t>& supp_gids, int namespace_flags,
                  const std::string& seclabel, Subcontext* subcontext_for_restart_commands,
-                 const std::vector<std::string>& args, bool from_apex)
+                 const std::string& filename, const std::vector<std::string>& args)
     : name_(name),
       classnames_({"default"}),
       flags_(flags),
@@ -156,7 +156,7 @@
       oom_score_adjust_(DEFAULT_OOM_SCORE_ADJUST),
       start_order_(0),
       args_(args),
-      from_apex_(from_apex) {}
+      filename_(filename) {}
 
 void Service::NotifyStateChange(const std::string& new_state) const {
     if ((flags_ & SVC_TEMPORARY) != 0) {
@@ -860,7 +860,7 @@
     }
 
     return std::make_unique<Service>(name, flags, *uid, *gid, supp_gids, namespace_flags, seclabel,
-                                     nullptr, str_args, false);
+                                     nullptr, /*filename=*/"", str_args);
 }
 
 // This is used for snapuserd_proxy, which hands off a socket to snapuserd. It's
diff --git a/init/service.h b/init/service.h
index 4adbaa2..f7f32d9 100644
--- a/init/service.h
+++ b/init/service.h
@@ -66,12 +66,12 @@
 
   public:
     Service(const std::string& name, Subcontext* subcontext_for_restart_commands,
-            const std::vector<std::string>& args, bool from_apex = false);
+            const std::string& filename, const std::vector<std::string>& args);
 
     Service(const std::string& name, unsigned flags, uid_t uid, gid_t gid,
             const std::vector<gid_t>& supp_gids, int namespace_flags, const std::string& seclabel,
-            Subcontext* subcontext_for_restart_commands, const std::vector<std::string>& args,
-            bool from_apex = false);
+            Subcontext* subcontext_for_restart_commands, const std::string& filename,
+            const std::vector<std::string>& args);
 
     static Result<std::unique_ptr<Service>> MakeTemporaryOneshotService(
             const std::vector<std::string>& args);
@@ -133,7 +133,7 @@
     const std::vector<std::string>& args() const { return args_; }
     bool is_updatable() const { return updatable_; }
     bool is_post_data() const { return post_data_; }
-    bool is_from_apex() const { return from_apex_; }
+    bool is_from_apex() const { return base::StartsWith(filename_, "/apex/"); }
     void set_oneshot(bool value) {
         if (value) {
             flags_ |= SVC_ONESHOT;
@@ -225,7 +225,7 @@
 
     std::optional<std::string> on_failure_reboot_target_;
 
-    bool from_apex_ = false;
+    std::string filename_;
 };
 
 }  // namespace init
diff --git a/init/service_parser.cpp b/init/service_parser.cpp
index 9e914ee..32c57c4 100644
--- a/init/service_parser.cpp
+++ b/init/service_parser.cpp
@@ -647,7 +647,7 @@
         }
     }
 
-    service_ = std::make_unique<Service>(name, restart_action_subcontext, str_args, from_apex_);
+    service_ = std::make_unique<Service>(name, restart_action_subcontext, filename, str_args);
     return {};
 }
 
diff --git a/init/service_parser.h b/init/service_parser.h
index 0fd2da5..54503dd 100644
--- a/init/service_parser.h
+++ b/init/service_parser.h
@@ -31,13 +31,11 @@
   public:
     ServiceParser(
             ServiceList* service_list, Subcontext* subcontext,
-            const std::optional<InterfaceInheritanceHierarchyMap>& interface_inheritance_hierarchy,
-            bool from_apex = false)
+            const std::optional<InterfaceInheritanceHierarchyMap>& interface_inheritance_hierarchy)
         : service_list_(service_list),
           subcontext_(subcontext),
           interface_inheritance_hierarchy_(interface_inheritance_hierarchy),
-          service_(nullptr),
-          from_apex_(from_apex) {}
+          service_(nullptr) {}
     Result<void> ParseSection(std::vector<std::string>&& args, const std::string& filename,
                               int line) override;
     Result<void> ParseLineSection(std::vector<std::string>&& args, int line) override;
@@ -92,7 +90,6 @@
     std::optional<InterfaceInheritanceHierarchyMap> interface_inheritance_hierarchy_;
     std::unique_ptr<Service> service_;
     std::string filename_;
-    bool from_apex_ = false;
 };
 
 }  // namespace init
diff --git a/init/service_test.cpp b/init/service_test.cpp
index 22ee844..87a2ce5 100644
--- a/init/service_test.cpp
+++ b/init/service_test.cpp
@@ -39,7 +39,7 @@
 
     std::vector<std::string> dummy_args{"/bin/test"};
     Service* service_in_old_memory =
-        new (old_memory) Service("test_old_memory", nullptr, dummy_args);
+        new (old_memory) Service("test_old_memory", nullptr, /*filename=*/"", dummy_args);
 
     EXPECT_EQ(0U, service_in_old_memory->flags());
     EXPECT_EQ(0, service_in_old_memory->pid());
@@ -58,7 +58,8 @@
     }
 
     Service* service_in_old_memory2 = new (old_memory) Service(
-            "test_old_memory", 0U, 0U, 0U, std::vector<gid_t>(), 0U, "", nullptr, dummy_args);
+            "test_old_memory", 0U, 0U, 0U, std::vector<gid_t>(), 0U, "",
+            nullptr, /*filename=*/"", dummy_args);
 
     EXPECT_EQ(0U, service_in_old_memory2->flags());
     EXPECT_EQ(0, service_in_old_memory2->pid());
diff --git a/init/subcontext.cpp b/init/subcontext.cpp
index bd2bec5..961e006 100644
--- a/init/subcontext.cpp
+++ b/init/subcontext.cpp
@@ -251,11 +251,8 @@
 }
 
 bool Subcontext::PathMatchesSubcontext(const std::string& path) const {
-    static const std::string kApexDir = "/apex/";
-    if (StartsWith(path, kApexDir)) {
-        auto begin = kApexDir.size();
-        auto end = path.find('/', begin);
-        auto apex_name = path.substr(begin, end - begin);
+    auto apex_name = GetApexNameFromFileName(path);
+    if (!apex_name.empty()) {
         return std::find(apex_list_.begin(), apex_list_.end(), apex_name) != apex_list_.end();
     }
     for (const auto& prefix : path_prefixes_) {
diff --git a/init/util.cpp b/init/util.cpp
index 523cce4..bfc3fb6 100644
--- a/init/util.cpp
+++ b/init/util.cpp
@@ -738,5 +738,15 @@
     return has;
 }
 
+std::string GetApexNameFromFileName(const std::string& path) {
+    static const std::string kApexDir = "/apex/";
+    if (StartsWith(path, kApexDir)) {
+        auto begin = kApexDir.size();
+        auto end = path.find('/', begin);
+        return path.substr(begin, end - begin);
+    }
+    return "";
+}
+
 }  // namespace init
 }  // namespace android
diff --git a/init/util.h b/init/util.h
index 099b9ee..daec470 100644
--- a/init/util.h
+++ b/init/util.h
@@ -107,5 +107,7 @@
 
 bool IsMicrodroid();
 bool Has32BitAbi();
+
+std::string GetApexNameFromFileName(const std::string& path);
 }  // namespace init
 }  // namespace android
diff --git a/trusty/storage/proxy/proxy.c b/trusty/storage/proxy/proxy.c
index 2620034..7cbc24f 100644
--- a/trusty/storage/proxy/proxy.c
+++ b/trusty/storage/proxy/proxy.c
@@ -70,49 +70,6 @@
     exit(code);
 }
 
-static int drop_privs(void) {
-    struct __user_cap_header_struct capheader;
-    struct __user_cap_data_struct capdata[2];
-
-    if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) < 0) {
-        return -1;
-    }
-
-    /*
-     * ensure we're running as the system user
-     */
-    if (setgid(AID_SYSTEM) != 0) {
-        return -1;
-    }
-
-    if (setuid(AID_SYSTEM) != 0) {
-        return -1;
-    }
-
-    /*
-     * drop all capabilities except SYS_RAWIO
-     */
-    memset(&capheader, 0, sizeof(capheader));
-    memset(&capdata, 0, sizeof(capdata));
-    capheader.version = _LINUX_CAPABILITY_VERSION_3;
-    capheader.pid = 0;
-
-    capdata[CAP_TO_INDEX(CAP_SYS_RAWIO)].permitted = CAP_TO_MASK(CAP_SYS_RAWIO);
-    capdata[CAP_TO_INDEX(CAP_SYS_RAWIO)].effective = CAP_TO_MASK(CAP_SYS_RAWIO);
-
-    if (capset(&capheader, &capdata[0]) < 0) {
-        return -1;
-    }
-
-    /*
-     * No access for group and other. We need execute access for user to create
-     * an accessible directory.
-     */
-    umask(S_IRWXG | S_IRWXO);
-
-    return 0;
-}
-
 static int handle_req(struct storage_msg* msg, const void* req, size_t req_len) {
     int rc;
 
@@ -260,8 +217,11 @@
 int main(int argc, char* argv[]) {
     int rc;
 
-    /* drop privileges */
-    if (drop_privs() < 0) return EXIT_FAILURE;
+    /*
+     * No access for group and other. We need execute access for user to create
+     * an accessible directory.
+     */
+    umask(S_IRWXG | S_IRWXO);
 
     /* parse arguments */
     parse_args(argc, argv);