diff --git a/adb/commandline.cpp b/adb/commandline.cpp
index ecaab83..4538b04 100644
--- a/adb/commandline.cpp
+++ b/adb/commandline.cpp
@@ -43,7 +43,8 @@
 static int do_cmd(transport_type ttype, const char* serial, const char *cmd, ...);
 
 int find_sync_dirs(const char *srcarg,
-        char **android_srcdir_out, char **data_srcdir_out, char **vendor_srcdir_out);
+        char **system_srcdir_out, char **data_srcdir_out, char **vendor_srcdir_out,
+        char **oem_srcdir_out);
 int install_app(transport_type transport, const char* serial, int argc,
                 const char** argv);
 int install_multiple_app(transport_type transport, const char* serial, int argc,
@@ -206,7 +207,7 @@
         "  adb get-serialno             - prints: <serial-number>\n"
         "  adb get-devpath              - prints: <device-path>\n"
         "  adb status-window            - continuously print device status for a specified device\n"
-        "  adb remount                  - remounts the /system and /vendor (if present) partitions on the device read-write\n"
+        "  adb remount                  - remounts the /system, /vendor (if present) and /oem (if present) partitions on the device read-write\n"
         "  adb reboot [bootloader|recovery] - reboots the device, optionally into the bootloader or recovery program\n"
         "  adb reboot-bootloader        - reboots the device into the bootloader\n"
         "  adb root                     - restarts the adbd daemon with root permissions\n"
@@ -222,9 +223,9 @@
         "adb sync notes: adb sync [ <directory> ]\n"
         "  <localdir> can be interpreted in several ways:\n"
         "\n"
-        "  - If <directory> is not specified, /system, /vendor (if present), and /data partitions will be updated.\n"
+        "  - If <directory> is not specified, /system, /vendor (if present), /oem (if present) and /data partitions will be updated.\n"
         "\n"
-        "  - If it is \"system\", \"vendor\" or \"data\", only the corresponding partition\n"
+        "  - If it is \"system\", \"vendor\", \"oem\" or \"data\", only the corresponding partition\n"
         "    is updated.\n"
         "\n"
         "environmental variables:\n"
@@ -1633,7 +1634,8 @@
     }
     else if (!strcmp(argv[0], "sync")) {
         const char* srcarg;
-        char *android_srcpath, *data_srcpath, *vendor_srcpath;
+        char *system_srcpath, *data_srcpath, *vendor_srcpath, *oem_srcpath;
+
         int listonly = 0;
 
         int ret;
@@ -1653,18 +1655,22 @@
         } else {
             return usage();
         }
-        ret = find_sync_dirs(srcarg, &android_srcpath, &data_srcpath, &vendor_srcpath);
+        ret = find_sync_dirs(srcarg, &system_srcpath, &data_srcpath, &vendor_srcpath,
+                &oem_srcpath);
         if (ret != 0) return usage();
 
-        if (android_srcpath != NULL)
-            ret = do_sync_sync(android_srcpath, "/system", listonly);
+        if (system_srcpath != NULL)
+            ret = do_sync_sync(system_srcpath, "/system", listonly);
         if (ret == 0 && vendor_srcpath != NULL)
             ret = do_sync_sync(vendor_srcpath, "/vendor", listonly);
+        if(ret == 0 && oem_srcpath != NULL)
+            ret = do_sync_sync(oem_srcpath, "/oem", listonly);
         if (ret == 0 && data_srcpath != NULL)
             ret = do_sync_sync(data_srcpath, "/data", listonly);
 
-        free(android_srcpath);
+        free(system_srcpath);
         free(vendor_srcpath);
+        free(oem_srcpath);
         free(data_srcpath);
         return ret;
     }
@@ -1770,49 +1776,60 @@
 }
 
 int find_sync_dirs(const char *srcarg,
-        char **android_srcdir_out, char **data_srcdir_out, char **vendor_srcdir_out)
+        char **system_srcdir_out, char **data_srcdir_out, char **vendor_srcdir_out,
+        char **oem_srcdir_out)
 {
-    char *android_srcdir = NULL, *data_srcdir = NULL, *vendor_srcdir = NULL;
+    char *system_srcdir = NULL, *data_srcdir = NULL, *vendor_srcdir = NULL, *oem_srcdir = NULL;
     struct stat st;
 
     if(srcarg == NULL) {
-        android_srcdir = product_file("system");
+        system_srcdir = product_file("system");
         data_srcdir = product_file("data");
         vendor_srcdir = product_file("vendor");
-        /* Check if vendor partition exists */
+        oem_srcdir = product_file("oem");
+        // Check if vendor partition exists.
         if (lstat(vendor_srcdir, &st) || !S_ISDIR(st.st_mode))
             vendor_srcdir = NULL;
+        // Check if oem partition exists.
+        if (lstat(oem_srcdir, &st) || !S_ISDIR(st.st_mode))
+            oem_srcdir = NULL;
     } else {
-        /* srcarg may be "data", "system" or NULL.
-         * if srcarg is NULL, then both data and system are synced
-         */
+        // srcarg may be "data", "system", "vendor", "oem" or NULL.
+        // If srcarg is NULL, then all partitions are synced.
         if(strcmp(srcarg, "system") == 0) {
-            android_srcdir = product_file("system");
+            system_srcdir = product_file("system");
         } else if(strcmp(srcarg, "data") == 0) {
             data_srcdir = product_file("data");
         } else if(strcmp(srcarg, "vendor") == 0) {
             vendor_srcdir = product_file("vendor");
+        } else if(strcmp(srcarg, "oem") == 0) {
+            oem_srcdir = product_file("oem");
         } else {
-            /* It's not "system", "vendor", or "data".
-             */
+            // It's not "system", "data", "vendor", or "oem".
             return 1;
         }
     }
 
-    if(android_srcdir_out != NULL)
-        *android_srcdir_out = android_srcdir;
+    if(system_srcdir_out != NULL)
+        *system_srcdir_out = system_srcdir;
     else
-        free(android_srcdir);
+        free(system_srcdir);
 
     if(vendor_srcdir_out != NULL)
         *vendor_srcdir_out = vendor_srcdir;
     else
         free(vendor_srcdir);
 
+    if(oem_srcdir_out != NULL)
+        *oem_srcdir_out = oem_srcdir;
+    else
+        free(oem_srcdir);
+
     if(data_srcdir_out != NULL)
-            *data_srcdir_out = data_srcdir;
-        else
-            free(data_srcdir);
+        *data_srcdir_out = data_srcdir;
+    else
+        free(data_srcdir);
+
     return 0;
 }
 
diff --git a/adb/file_sync_service.cpp b/adb/file_sync_service.cpp
index 2864b38..ac01678 100644
--- a/adb/file_sync_service.cpp
+++ b/adb/file_sync_service.cpp
@@ -33,15 +33,11 @@
 #include "file_sync_service.h"
 #include "private/android_filesystem_config.h"
 
-/* TODO: use fs_config to configure permissions on /data */
-static bool is_on_system(const char *name) {
-    const char *SYSTEM = "/system/";
-    return (strncmp(SYSTEM, name, strlen(SYSTEM)) == 0);
-}
-
-static bool is_on_vendor(const char *name) {
-    const char *VENDOR = "/vendor/";
-    return (strncmp(VENDOR, name, strlen(VENDOR)) == 0);
+static bool should_use_fs_config(const char* path) {
+    // TODO: use fs_config to configure permissions on /data.
+    return strncmp("/system/", path, strlen("/system/")) == 0 ||
+           strncmp("/vendor/", path, strlen("/vendor/")) == 0 ||
+           strncmp("/oem/", path, strlen("/oem/")) == 0;
 }
 
 static int mkdirs(char *name)
@@ -59,7 +55,7 @@
         x = adb_dirstart(x);
         if(x == 0) return 0;
         *x = 0;
-        if (is_on_system(name) || is_on_vendor(name)) {
+        if (should_use_fs_config(name)) {
             fs_config(name, 1, &uid, &gid, &mode, &cap);
         }
         ret = adb_mkdir(name, mode);
@@ -368,7 +364,7 @@
     if(*tmp == '/') {
         tmp++;
     }
-    if (is_on_system(path) || is_on_vendor(path)) {
+    if (should_use_fs_config(path)) {
         fs_config(tmp, 0, &uid, &gid, &mode, &cap);
     }
     return handle_send_file(s, path, uid, gid, mode, buffer, do_unlink);
diff --git a/adb/remount_service.cpp b/adb/remount_service.cpp
index 414b316..a83d5b1 100644
--- a/adb/remount_service.cpp
+++ b/adb/remount_service.cpp
@@ -23,6 +23,8 @@
 #include <sys/mount.h>
 #include <unistd.h>
 
+#include <string>
+
 #include "sysdeps.h"
 
 #define  TRACE_TAG  TRACE_ADB
@@ -32,10 +34,10 @@
 
 static int system_ro = 1;
 static int vendor_ro = 1;
+static int oem_ro = 1;
 
 /* Returns the device used to mount a directory in /proc/mounts */
-static char *find_mount(const char *dir)
-{
+static std::string find_mount(const char *dir) {
     FILE* fp;
     struct mntent* mentry;
     char* device = NULL;
@@ -45,7 +47,7 @@
     }
     while ((mentry = getmntent(fp)) != NULL) {
         if (strcmp(dir, mentry->mnt_dir) == 0) {
-            device = strdup(mentry->mnt_fsname);
+            device = mentry->mnt_fsname;
             break;
         }
     }
@@ -53,64 +55,53 @@
     return device;
 }
 
-static int hasVendorPartition()
-{
-    struct stat info;
-    if (!lstat("/vendor", &info))
-        if ((info.st_mode & S_IFMT) == S_IFDIR)
-          return true;
-    return false;
+static bool has_partition(const char* path) {
+    struct stat sb;
+    return (lstat(path, &sb) == 0 && S_ISDIR(sb.st_mode));
 }
 
-int make_block_device_writable(const char* dev)
-{
-    int fd = -1;
+int make_block_device_writable(const std::string& dev) {
+    int fd = unix_open(dev.c_str(), O_RDONLY | O_CLOEXEC);
+    if (fd == -1) {
+        return -1;
+    }
+
+    int result = -1;
     int OFF = 0;
-    int rc = -1;
-
-    if (!dev)
-        goto errout;
-
-    fd = unix_open(dev, O_RDONLY | O_CLOEXEC);
-    if (fd < 0)
-        goto errout;
-
-    if (ioctl(fd, BLKROSET, &OFF)) {
-        goto errout;
+    if (!ioctl(fd, BLKROSET, &OFF)) {
+        result = 0;
     }
+    adb_close(fd);
 
-    rc = 0;
-
-errout:
-    if (fd >= 0) {
-        adb_close(fd);
-    }
-    return rc;
+    return result;
 }
 
-/* Init mounts /system as read only, remount to enable writes. */
-static int remount(const char* dir, int* dir_ro)
-{
-    char *dev = 0;
-    int rc = -1;
-
-    dev = find_mount(dir);
-
-    if (!dev || make_block_device_writable(dev)) {
-        goto errout;
+// Init mounts /system as read only, remount to enable writes.
+static int remount(const char* dir, int* dir_ro) {
+    std::string dev(find_mount(dir));
+    if (dev.empty() || make_block_device_writable(dev)) {
+        return -1;
     }
 
-    rc = mount(dev, dir, "none", MS_REMOUNT, NULL);
+    int rc = mount(dev.c_str(), dir, "none", MS_REMOUNT, NULL);
     *dir_ro = rc;
-
-errout:
-    free(dev);
     return rc;
 }
 
-void remount_service(int fd, void *cookie)
-{
-    char buffer[200];
+static bool remount_partition(int fd, const char* partition, int* ro) {
+  if (!has_partition(partition)) {
+    return true;
+  }
+  if (remount(partition, ro)) {
+    char buf[200];
+    snprintf(buf, sizeof(buf), "remount of %s failed: %s\n", partition, strerror(errno));
+    WriteStringFully(fd, buf);
+    return false;
+  }
+  return true;
+}
+
+void remount_service(int fd, void* cookie) {
     char prop_buf[PROPERTY_VALUE_MAX];
 
     if (getuid() != 0) {
@@ -133,6 +124,7 @@
     if (system_verified || vendor_verified) {
         // Allow remount but warn of likely bad effects
         bool both = system_verified && vendor_verified;
+        char buffer[200];
         snprintf(buffer, sizeof(buffer),
                  "dm_verity is enabled on the %s%s%s partition%s.\n",
                  system_verified ? "system" : "",
@@ -147,23 +139,12 @@
         WriteStringFully(fd, buffer);
     }
 
-    if (remount("/system", &system_ro)) {
-        snprintf(buffer, sizeof(buffer), "remount of system failed: %s\n",strerror(errno));
-        WriteStringFully(fd, buffer);
-    }
+    bool success = true;
+    success &= remount_partition(fd, "/system", &system_ro);
+    success &= remount_partition(fd, "/vendor", &vendor_ro);
+    success &= remount_partition(fd, "/oem", &oem_ro);
 
-    if (hasVendorPartition()) {
-        if (remount("/vendor", &vendor_ro)) {
-            snprintf(buffer, sizeof(buffer), "remount of vendor failed: %s\n",strerror(errno));
-            WriteStringFully(fd, buffer);
-        }
-    }
-
-    if (!system_ro && (!vendor_ro || !hasVendorPartition()))
-        WriteStringFully(fd, "remount succeeded\n");
-    else {
-        WriteStringFully(fd, "remount failed\n");
-    }
+    WriteStringFully(fd, success ? "remount succeeded\n" : "remount failed\n");
 
     adb_close(fd);
 }