diff --git a/fs_mgr/fs_mgr_remount.cpp b/fs_mgr/fs_mgr_remount.cpp
index e2a4d16..24044d8 100644
--- a/fs_mgr/fs_mgr_remount.cpp
+++ b/fs_mgr/fs_mgr_remount.cpp
@@ -176,6 +176,15 @@
         fstab_read = android::fs_mgr::ReadFstabFromFile(fstab_file, &fstab);
     } else {
         fstab_read = android::fs_mgr::ReadDefaultFstab(&fstab);
+        // Manufacture a / entry from /proc/mounts if missing.
+        if (!GetEntryForMountPoint(&fstab, "/system") && !GetEntryForMountPoint(&fstab, "/")) {
+            android::fs_mgr::Fstab mounts;
+            if (android::fs_mgr::ReadFstabFromFile("/proc/mounts", &mounts)) {
+                if (auto entry = GetEntryForMountPoint(&mounts, "/")) {
+                    if (entry->fs_type != "rootfs") fstab.emplace_back(*entry);
+                }
+            }
+        }
     }
     if (!fstab_read || fstab.empty()) {
         PLOG(ERROR) << "Failed to read fstab";
@@ -211,21 +220,21 @@
         // Do we know about the partition?
         auto it = std::find_if(fstab.begin(), fstab.end(), find_part);
         if (it == fstab.end()) {
-            LOG(ERROR) << "Unknown partition " << partition << ", skipping";
+            LOG(ERROR) << "Unknown partition " << argv[optind] << ", skipping";
             retval = UNKNOWN_PARTITION;
             continue;
         }
         // Is that one covered by an existing overlayfs?
         auto wrap = is_wrapped(overlayfs_candidates, *it);
         if (wrap) {
-            LOG(INFO) << "partition " << partition << " covered by overlayfs for "
+            LOG(INFO) << "partition " << argv[optind] << " covered by overlayfs for "
                       << wrap->mount_point << ", switching";
             partition = system_mount_point(*wrap);
         }
         // Is it a remountable partition?
         it = std::find_if(all.begin(), all.end(), find_part);
         if (it == all.end()) {
-            LOG(ERROR) << "Invalid partition " << partition << ", skipping";
+            LOG(ERROR) << "Invalid partition " << argv[optind] << ", skipping";
             retval = INVALID_PARTITION;
             continue;
         }
diff --git a/fs_mgr/tests/adb-remount-test.sh b/fs_mgr/tests/adb-remount-test.sh
index ec6eb52..b95e54e 100755
--- a/fs_mgr/tests/adb-remount-test.sh
+++ b/fs_mgr/tests/adb-remount-test.sh
@@ -514,8 +514,8 @@
     cat -
   fi |
   grep -v \
-    -e "^\(overlay\|tmpfs\|none\|sysfs\|proc\|selinuxfs\|debugfs\) " \
-    -e "^\(bpf\|cg2_bpf\|pstore\|tracefs\|adb\|mtp\|ptp\|devpts\) " \
+    -e "^\(overlay\|tmpfs\|none\|sysfs\|proc\|selinuxfs\|debugfs\|bpf\) " \
+    -e "^\(binfmt_misc\|cg2_bpf\|pstore\|tracefs\|adb\|mtp\|ptp\|devpts\) " \
     -e "^\(/data/media\|/dev/block/loop[0-9]*\) " \
     -e "^rootfs / rootfs rw," \
     -e " /\(cache\|mnt/scratch\|mnt/vendor/persist\|persist\|metadata\) "
@@ -608,7 +608,7 @@
 
 D=`get_property ro.serialno`
 [ -n "${D}" ] || D=`get_property ro.boot.serialno`
-[ -z "${D}" ] || ANDROID_SERIAL=${D}
+[ -z "${D}" -o -n "${ANDROID_SERIAL}" ] || ANDROID_SERIAL=${D}
 USB_SERIAL=
 [ -z "${ANDROID_SERIAL}" ] || USB_SERIAL=`find /sys/devices -name serial |
                                           grep usb |
@@ -998,8 +998,14 @@
 echo "${GREEN}[ RUN      ]${NORMAL} flash vendor, confirm its content disappears" >&2
 
 H=`adb_sh echo '${HOSTNAME}' </dev/null 2>/dev/null`
+is_bootloader_fastboot=false
+# cuttlefish?
+[ X"${H}" != X"${H#vsoc}" ] || is_bootloader_fastboot=true
 is_userspace_fastboot=false
-if [ -z "${ANDROID_PRODUCT_OUT}" ]; then
+
+if ! ${is_bootloader_fastboot}; then
+  echo "${ORANGE}[  WARNING ]${NORMAL} does not support fastboot, skipping"
+elif [ -z "${ANDROID_PRODUCT_OUT}" ]; then
   echo "${ORANGE}[  WARNING ]${NORMAL} build tree not setup, skipping"
 elif [ ! -s "${ANDROID_PRODUCT_OUT}/vendor.img" ]; then
   echo "${ORANGE}[  WARNING ]${NORMAL} vendor image missing, skipping"