diff --git a/fs_mgr/fs_mgr_slotselect.cpp b/fs_mgr/fs_mgr_slotselect.cpp
index 33fd56240..0a113b47e 100644
--- a/fs_mgr/fs_mgr_slotselect.cpp
+++ b/fs_mgr/fs_mgr_slotselect.cpp
@@ -40,7 +40,7 @@ bool fs_mgr_update_for_slotselect(struct fstab *fstab) {
             char *tmp;
             if (ab_suffix.empty()) {
                 ab_suffix = fs_mgr_get_slot_suffix();
-                // Returns false as non A/B devices should not have MF_SLOTSELECT.
+                // Return false if failed to get ab_suffix when MF_SLOTSELECT is specified.
                 if (ab_suffix.empty()) return false;
             }
             if (asprintf(&tmp, "%s%s", fstab->recs[n].blk_device, ab_suffix.c_str()) > 0) {
diff --git a/init/init_first_stage.cpp b/init/init_first_stage.cpp
index 0f7e38fa6..6fa07e728 100644
--- a/init/init_first_stage.cpp
+++ b/init/init_first_stage.cpp
@@ -118,7 +118,10 @@ static bool inline IsRecoveryMode() {
 FirstStageMount::FirstStageMount()
     : need_dm_verity_(false), device_tree_fstab_(fs_mgr_read_fstab_dt(), fs_mgr_free_fstab) {
     if (!device_tree_fstab_) {
-        LOG(ERROR) << "Failed to read fstab from device tree";
+        // The client of FirstStageMount should check the existence of fstab in device-tree
+        // in advance, without parsing it. Reaching here means there is a FATAL error when
+        // parsing the fstab. So stop here to expose the failure.
+        LOG(FATAL) << "Failed to read fstab from device tree";
         return;
     }
     // Stores device_tree_fstab_->recs[] into mount_fstab_recs_ (vector<fstab_rec*>)