diff --git a/FsCrypt.cpp b/FsCrypt.cpp
index 4f1f5b2..7fe8be4 100644
--- a/FsCrypt.cpp
+++ b/FsCrypt.cpp
@@ -603,7 +603,7 @@
     // only prepare DE storage here, since user 0's CE key won't be installed
     // yet unless it was just created.  The framework will prepare the user's CE
     // storage later, once their CE key is installed.
-    if (!fscrypt_prepare_user_storage("", 0, 0, android::os::IVold::STORAGE_FLAG_DE)) {
+    if (!fscrypt_prepare_user_storage("", 0, android::os::IVold::STORAGE_FLAG_DE)) {
         LOG(ERROR) << "Failed to prepare user 0 storage";
         return false;
     }
@@ -613,14 +613,14 @@
 }
 
 // Creates the CE and DE keys for a new user.
-bool fscrypt_create_user_keys(userid_t user_id, int serial, bool ephemeral) {
-    LOG(DEBUG) << "fscrypt_create_user_keys for " << user_id << " serial " << serial;
+bool fscrypt_create_user_keys(userid_t user_id, bool ephemeral) {
+    LOG(DEBUG) << "fscrypt_create_user_keys for " << user_id;
     if (!IsFbeEnabled()) {
         return true;
     }
     // FIXME test for existence of key that is not loaded yet
     if (s_ce_policies.count(user_id) != 0) {
-        LOG(ERROR) << "Already exists, can't create keys for " << user_id << " serial " << serial;
+        LOG(ERROR) << "Already exists, can't create keys for " << user_id;
         // FIXME should we fail the command?
         return true;
     }
@@ -847,8 +847,8 @@
 // Unlocks internal CE storage for the given user.  This only unlocks internal storage, since
 // fscrypt_prepare_user_storage() has to be called for each adoptable storage volume anyway (since
 // the volume might have been absent when the user was created), and that handles the unlocking.
-bool fscrypt_unlock_ce_storage(userid_t user_id, int serial, const std::string& secret_hex) {
-    LOG(DEBUG) << "fscrypt_unlock_ce_storage " << user_id << " serial=" << serial;
+bool fscrypt_unlock_ce_storage(userid_t user_id, const std::string& secret_hex) {
+    LOG(DEBUG) << "fscrypt_unlock_ce_storage " << user_id;
     if (!IsFbeEnabled()) return true;
     if (s_ce_policies.count(user_id) != 0) {
         LOG(WARNING) << "CE storage for user " << user_id << " is already unlocked";
@@ -883,10 +883,9 @@
     return true;
 }
 
-bool fscrypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_id, int serial,
-                                  int flags) {
+bool fscrypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_id, int flags) {
     LOG(DEBUG) << "fscrypt_prepare_user_storage for volume " << escape_empty(volume_uuid)
-               << ", user " << user_id << ", serial " << serial << ", flags " << flags;
+               << ", user " << user_id << ", flags " << flags;
 
     // Internal storage must be prepared before adoptable storage, since the
     // user's volume keys are stored in their internal storage.
diff --git a/FsCrypt.h b/FsCrypt.h
index f5c367c..afcedfb 100644
--- a/FsCrypt.h
+++ b/FsCrypt.h
@@ -23,17 +23,16 @@
 
 bool fscrypt_init_user0();
 extern bool fscrypt_init_user0_done;
-bool fscrypt_create_user_keys(userid_t user_id, int serial, bool ephemeral);
+bool fscrypt_create_user_keys(userid_t user_id, bool ephemeral);
 bool fscrypt_destroy_user_keys(userid_t user_id);
 bool fscrypt_set_ce_key_protection(userid_t user_id, const std::string& secret);
 void fscrypt_deferred_fixate_ce_keys();
 
 std::vector<int> fscrypt_get_unlocked_users();
-bool fscrypt_unlock_ce_storage(userid_t user_id, int serial, const std::string& secret);
+bool fscrypt_unlock_ce_storage(userid_t user_id, const std::string& secret);
 bool fscrypt_lock_ce_storage(userid_t user_id);
 
-bool fscrypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_id, int serial,
-                                  int flags);
+bool fscrypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_id, int flags);
 bool fscrypt_destroy_user_storage(const std::string& volume_uuid, userid_t user_id, int flags);
 
 bool fscrypt_destroy_volume_keys(const std::string& volume_uuid);
diff --git a/VoldNativeService.cpp b/VoldNativeService.cpp
index c39604b..65731af 100644
--- a/VoldNativeService.cpp
+++ b/VoldNativeService.cpp
@@ -607,12 +607,11 @@
     return translateBool(setKeyStorageBindingSeed(seed));
 }
 
-binder::Status VoldNativeService::createUserStorageKeys(int32_t userId, int32_t userSerial,
-                                                        bool ephemeral) {
+binder::Status VoldNativeService::createUserStorageKeys(int32_t userId, bool ephemeral) {
     ENFORCE_SYSTEM_OR_ROOT;
     ACQUIRE_CRYPT_LOCK;
 
-    return translateBool(fscrypt_create_user_keys(userId, userSerial, ephemeral));
+    return translateBool(fscrypt_create_user_keys(userId, ephemeral));
 }
 
 binder::Status VoldNativeService::destroyUserStorageKeys(int32_t userId) {
@@ -638,12 +637,11 @@
     return Ok();
 }
 
-binder::Status VoldNativeService::unlockCeStorage(int32_t userId, int32_t userSerial,
-                                                  const std::string& secret) {
+binder::Status VoldNativeService::unlockCeStorage(int32_t userId, const std::string& secret) {
     ENFORCE_SYSTEM_OR_ROOT;
     ACQUIRE_CRYPT_LOCK;
 
-    return translateBool(fscrypt_unlock_ce_storage(userId, userSerial, secret));
+    return translateBool(fscrypt_unlock_ce_storage(userId, secret));
 }
 
 binder::Status VoldNativeService::lockCeStorage(int32_t userId) {
@@ -654,15 +652,14 @@
 }
 
 binder::Status VoldNativeService::prepareUserStorage(const std::optional<std::string>& uuid,
-                                                     int32_t userId, int32_t userSerial,
-                                                     int32_t flags) {
+                                                     int32_t userId, int32_t flags) {
     ENFORCE_SYSTEM_OR_ROOT;
     std::string empty_string = "";
     auto uuid_ = uuid ? *uuid : empty_string;
     CHECK_ARGUMENT_HEX(uuid_);
 
     ACQUIRE_CRYPT_LOCK;
-    return translateBool(fscrypt_prepare_user_storage(uuid_, userId, userSerial, flags));
+    return translateBool(fscrypt_prepare_user_storage(uuid_, userId, flags));
 }
 
 binder::Status VoldNativeService::destroyUserStorage(const std::optional<std::string>& uuid,
diff --git a/VoldNativeService.h b/VoldNativeService.h
index e98aea8..d9aee57 100644
--- a/VoldNativeService.h
+++ b/VoldNativeService.h
@@ -112,17 +112,17 @@
 
     binder::Status setStorageBindingSeed(const std::vector<uint8_t>& seed);
 
-    binder::Status createUserStorageKeys(int32_t userId, int32_t userSerial, bool ephemeral);
+    binder::Status createUserStorageKeys(int32_t userId, bool ephemeral);
     binder::Status destroyUserStorageKeys(int32_t userId);
 
     binder::Status setCeStorageProtection(int32_t userId, const std::string& secret);
 
     binder::Status getUnlockedUsers(std::vector<int>* _aidl_return);
-    binder::Status unlockCeStorage(int32_t userId, int32_t userSerial, const std::string& secret);
+    binder::Status unlockCeStorage(int32_t userId, const std::string& secret);
     binder::Status lockCeStorage(int32_t userId);
 
     binder::Status prepareUserStorage(const std::optional<std::string>& uuid, int32_t userId,
-                                      int32_t userSerial, int32_t flags);
+                                      int32_t flags);
     binder::Status destroyUserStorage(const std::optional<std::string>& uuid, int32_t userId,
                                       int32_t flags);
 
diff --git a/binder/android/os/IVold.aidl b/binder/android/os/IVold.aidl
index 852e8af..229f173 100644
--- a/binder/android/os/IVold.aidl
+++ b/binder/android/os/IVold.aidl
@@ -85,17 +85,16 @@
 
     void setStorageBindingSeed(in byte[] seed);
 
-    void createUserStorageKeys(int userId, int userSerial, boolean ephemeral);
+    void createUserStorageKeys(int userId, boolean ephemeral);
     void destroyUserStorageKeys(int userId);
 
     void setCeStorageProtection(int userId, @utf8InCpp String secret);
 
     int[] getUnlockedUsers();
-    void unlockCeStorage(int userId, int userSerial, @utf8InCpp String secret);
+    void unlockCeStorage(int userId, @utf8InCpp String secret);
     void lockCeStorage(int userId);
 
-    void prepareUserStorage(@nullable @utf8InCpp String uuid, int userId, int userSerial,
-                            int storageFlags);
+    void prepareUserStorage(@nullable @utf8InCpp String uuid, int userId, int storageFlags);
     void destroyUserStorage(@nullable @utf8InCpp String uuid, int userId, int storageFlags);
 
     void prepareSandboxForApp(in @utf8InCpp String packageName, int appId,