diff --git a/common/protob/messages-management.proto b/common/protob/messages-management.proto
index 76b7fc76f1..c1ded4373a 100644
--- a/common/protob/messages-management.proto
+++ b/common/protob/messages-management.proto
@@ -153,7 +153,7 @@ message ApplySettings {
  * @next Failure
  */
 message ApplyFlags {
-    optional uint32 flags = 1;  // bitmask, can only set bits, not unset
+    required uint32 flags = 1;  // bitmask, can only set bits, not unset
 }
 
 /**
@@ -183,7 +183,7 @@ message ChangeWipeCode {
  * @next Failure
  */
 message SdProtect {
-    optional SdProtectOperationType operation = 1;
+    required SdProtectOperationType operation = 1;
     /**
     * Structure representing SD card protection operation
     */
@@ -296,7 +296,7 @@ message EntropyRequest {
  * @next Success
  */
 message EntropyAck {
-    optional bytes entropy = 1;     // 256 bits (32 bytes) of random data
+    required bytes entropy = 1;     // 256 bits (32 bytes) of random data
 }
 
 /**
@@ -337,7 +337,7 @@ message RecoveryDevice {
  * @next WordAck
  */
 message WordRequest {
-    optional WordRequestType type = 1;
+    required WordRequestType type = 1;
     /**
     * Type of Recovery Word request
     */
@@ -364,7 +364,7 @@ message WordAck {
  * @next Success
  */
 message SetU2FCounter {
-    optional uint32 u2f_counter = 1;
+    required uint32 u2f_counter = 1;
 }
 
 /**
@@ -380,7 +380,7 @@ message GetNextU2FCounter {
  * @end
  */
 message NextU2FCounter {
-    optional uint32 u2f_counter = 1;
+    required uint32 u2f_counter = 1;
 }
 
 /**
diff --git a/core/src/trezor/messages.py b/core/src/trezor/messages.py
index 6b03796a61..acefffb296 100644
--- a/core/src/trezor/messages.py
+++ b/core/src/trezor/messages.py
@@ -1791,12 +1791,12 @@ if TYPE_CHECKING:
             return isinstance(msg, cls)
 
     class ApplyFlags(protobuf.MessageType):
-        flags: int | None
+        flags: int
 
         def __init__(
             self,
             *,
-            flags: int | None = None,
+            flags: int,
         ) -> None:
             pass
 
@@ -1833,12 +1833,12 @@ if TYPE_CHECKING:
             return isinstance(msg, cls)
 
     class SdProtect(protobuf.MessageType):
-        operation: SdProtectOperationType | None
+        operation: SdProtectOperationType
 
         def __init__(
             self,
             *,
-            operation: SdProtectOperationType | None = None,
+            operation: SdProtectOperationType,
         ) -> None:
             pass
 
@@ -1977,12 +1977,12 @@ if TYPE_CHECKING:
             return isinstance(msg, cls)
 
     class EntropyAck(protobuf.MessageType):
-        entropy: bytes | None
+        entropy: bytes
 
         def __init__(
             self,
             *,
-            entropy: bytes | None = None,
+            entropy: bytes,
         ) -> None:
             pass
 
@@ -2021,12 +2021,12 @@ if TYPE_CHECKING:
             return isinstance(msg, cls)
 
     class WordRequest(protobuf.MessageType):
-        type: WordRequestType | None
+        type: WordRequestType
 
         def __init__(
             self,
             *,
-            type: WordRequestType | None = None,
+            type: WordRequestType,
         ) -> None:
             pass
 
@@ -2049,12 +2049,12 @@ if TYPE_CHECKING:
             return isinstance(msg, cls)
 
     class SetU2FCounter(protobuf.MessageType):
-        u2f_counter: int | None
+        u2f_counter: int
 
         def __init__(
             self,
             *,
-            u2f_counter: int | None = None,
+            u2f_counter: int,
         ) -> None:
             pass
 
@@ -2069,12 +2069,12 @@ if TYPE_CHECKING:
             return isinstance(msg, cls)
 
     class NextU2FCounter(protobuf.MessageType):
-        u2f_counter: int | None
+        u2f_counter: int
 
         def __init__(
             self,
             *,
-            u2f_counter: int | None = None,
+            u2f_counter: int,
         ) -> None:
             pass
 
diff --git a/legacy/firmware/fsm_msg_common.h b/legacy/firmware/fsm_msg_common.h
index f29eb3b335..a5aeaf16d3 100644
--- a/legacy/firmware/fsm_msg_common.h
+++ b/legacy/firmware/fsm_msg_common.h
@@ -315,11 +315,7 @@ void fsm_msgResetDevice(const ResetDevice *msg) {
 }
 
 void fsm_msgEntropyAck(const EntropyAck *msg) {
-  if (msg->has_entropy) {
-    reset_entropy(msg->entropy.bytes, msg->entropy.size);
-  } else {
-    reset_entropy(0, 0);
-  }
+  reset_entropy(msg->entropy.bytes, msg->entropy.size);
 }
 
 void fsm_msgBackupDevice(const BackupDevice *msg) {
@@ -477,9 +473,7 @@ void fsm_msgApplySettings(const ApplySettings *msg) {
 void fsm_msgApplyFlags(const ApplyFlags *msg) {
   CHECK_PIN
 
-  if (msg->has_flags) {
-    config_applyFlags(msg->flags);
-  }
+  config_applyFlags(msg->flags);
   fsm_sendSuccess(_("Flags applied"));
 }
 
@@ -539,7 +533,6 @@ void fsm_msgGetNextU2FCounter() {
   uint32_t counter = config_nextU2FCounter();
 
   RESP_INIT(NextU2FCounter);
-  resp->has_u2f_counter = true;
   resp->u2f_counter = counter;
   msg_write(MessageType_MessageType_NextU2FCounter, resp);
   layoutHome();
diff --git a/legacy/firmware/recovery.c b/legacy/firmware/recovery.c
index 9f5094abc6..db708915d3 100644
--- a/legacy/firmware/recovery.c
+++ b/legacy/firmware/recovery.c
@@ -145,7 +145,6 @@ static void format_number(char *dest, int number) {
 static void recovery_request(void) {
   WordRequest resp = {0};
   memzero(&resp, sizeof(WordRequest));
-  resp.has_type = true;
   if (awaiting_word == 1) {
     resp.type = WordRequestType_WordRequestType_Plain;
   } else if (word_index % 4 == 3) {
diff --git a/python/src/trezorlib/messages.py b/python/src/trezorlib/messages.py
index 106a1f35a2..7121f101d7 100644
--- a/python/src/trezorlib/messages.py
+++ b/python/src/trezorlib/messages.py
@@ -2690,13 +2690,13 @@ class ApplySettings(protobuf.MessageType):
 class ApplyFlags(protobuf.MessageType):
     MESSAGE_WIRE_TYPE = 28
     FIELDS = {
-        1: protobuf.Field("flags", "uint32", repeated=False, required=False),
+        1: protobuf.Field("flags", "uint32", repeated=False, required=True),
     }
 
     def __init__(
         self,
         *,
-        flags: Optional[int] = None,
+        flags: int,
     ) -> None:
         self.flags = flags
 
@@ -2732,13 +2732,13 @@ class ChangeWipeCode(protobuf.MessageType):
 class SdProtect(protobuf.MessageType):
     MESSAGE_WIRE_TYPE = 79
     FIELDS = {
-        1: protobuf.Field("operation", SdProtectOperationType, repeated=False, required=False),
+        1: protobuf.Field("operation", SdProtectOperationType, repeated=False, required=True),
     }
 
     def __init__(
         self,
         *,
-        operation: Optional[SdProtectOperationType] = None,
+        operation: SdProtectOperationType,
     ) -> None:
         self.operation = operation
 
@@ -2886,13 +2886,13 @@ class EntropyRequest(protobuf.MessageType):
 class EntropyAck(protobuf.MessageType):
     MESSAGE_WIRE_TYPE = 36
     FIELDS = {
-        1: protobuf.Field("entropy", "bytes", repeated=False, required=False),
+        1: protobuf.Field("entropy", "bytes", repeated=False, required=True),
     }
 
     def __init__(
         self,
         *,
-        entropy: Optional[bytes] = None,
+        entropy: bytes,
     ) -> None:
         self.entropy = entropy
 
@@ -2938,13 +2938,13 @@ class RecoveryDevice(protobuf.MessageType):
 class WordRequest(protobuf.MessageType):
     MESSAGE_WIRE_TYPE = 46
     FIELDS = {
-        1: protobuf.Field("type", WordRequestType, repeated=False, required=False),
+        1: protobuf.Field("type", WordRequestType, repeated=False, required=True),
     }
 
     def __init__(
         self,
         *,
-        type: Optional[WordRequestType] = None,
+        type: WordRequestType,
     ) -> None:
         self.type = type
 
@@ -2966,13 +2966,13 @@ class WordAck(protobuf.MessageType):
 class SetU2FCounter(protobuf.MessageType):
     MESSAGE_WIRE_TYPE = 63
     FIELDS = {
-        1: protobuf.Field("u2f_counter", "uint32", repeated=False, required=False),
+        1: protobuf.Field("u2f_counter", "uint32", repeated=False, required=True),
     }
 
     def __init__(
         self,
         *,
-        u2f_counter: Optional[int] = None,
+        u2f_counter: int,
     ) -> None:
         self.u2f_counter = u2f_counter
 
@@ -2984,13 +2984,13 @@ class GetNextU2FCounter(protobuf.MessageType):
 class NextU2FCounter(protobuf.MessageType):
     MESSAGE_WIRE_TYPE = 81
     FIELDS = {
-        1: protobuf.Field("u2f_counter", "uint32", repeated=False, required=False),
+        1: protobuf.Field("u2f_counter", "uint32", repeated=False, required=True),
     }
 
     def __init__(
         self,
         *,
-        u2f_counter: Optional[int] = None,
+        u2f_counter: int,
     ) -> None:
         self.u2f_counter = u2f_counter