diff --git a/api/src/api/backup.rs b/api/src/api/backup.rs
index c530ceb..dca9184 100644
--- a/api/src/api/backup.rs
+++ b/api/src/api/backup.rs
@@ -10,3 +10,25 @@ pub struct Shard {
     #[n(0)]
     pub payload: Vec<u8>,
 }
+
+#[quantum_link]
+pub struct BackupShardRequest(#[n(0)] pub Shard);
+
+#[quantum_link]
+pub enum BackupShardResponse {
+    #[n(0)]
+    Success,
+    #[n(1)]
+    Error(#[n(0)] String),
+}
+
+#[quantum_link]
+pub struct RestoreShardRequest;
+
+#[quantum_link]
+pub enum RestoreShardResponse {
+    #[n(0)]
+    Success(#[n(0)] Shard),
+    #[n(1)]
+    Error(#[n(0)] String),
+}
diff --git a/api/src/api/firmware.rs b/api/src/api/firmware.rs
index acd2bad..3943eb9 100644
--- a/api/src/api/firmware.rs
+++ b/api/src/api/firmware.rs
@@ -4,49 +4,70 @@ use minicbor_derive::{Decode, Encode};
 use quantum_link_macros::quantum_link;
 
 #[quantum_link]
-pub struct FirmwareUpdate {
+pub struct FirmwareUpdateCheckRequest {
+    #[n(0)]
+    pub current_version: String,
+}
+
+#[quantum_link]
+pub enum FirmwareUpdateCheckResponse {
+    #[n(0)]
+    Available(#[n(0)] FirmwareUpdateAvailable),
+    #[n(1)]
+    NotAvailable,
+}
+
+#[quantum_link]
+pub struct FirmwareUpdateAvailable {
     #[n(0)]
     pub version: String,
     #[n(1)]
-    pub timestamp: u32,
-    #[n(2)]
     pub changelog: String,
+    #[n(2)]
+    pub timestamp: u32,
+    #[n(3)]
+    pub size: u32,
 }
 
-impl FirmwareUpdate {
-    pub fn new(version: String, timestamp: u32, changelog: String) -> Self {
-        Self {
-            version,
-            timestamp,
-            changelog,
-        }
-    }
-
-    pub fn version(&self) -> &str {
-        &self.version
-    }
-
-    pub fn timestamp(&self) -> u32 {
-        self.timestamp
-    }
-
-    pub fn changelog(&self) -> &str {
-        &self.changelog
-    }
+#[quantum_link]
+pub struct FirmwareDownloadRequest {
+    #[n(0)]
+    pub version: String,
 }
 
 #[quantum_link]
-pub struct FirmwarePayload {
+pub enum FirmwareDownloadResponse {
     #[n(0)]
-    pub payload: Vec<u8>,
+    EnvoyDownloadProgress {
+        #[n(0)]
+        progress: f32,
+    },
+    #[n(1)]
+    Start {
+        #[n(0)]
+        total_chunks: u16,
+    },
+    #[n(2)]
+    Chunk(#[n(0)] FirmwareChunk),
+    #[n(3)]
+    Error(#[n(0)] String),
 }
 
-impl FirmwarePayload {
-    pub fn new(payload: Vec<u8>) -> Self {
-        Self { payload }
-    }
+#[quantum_link]
+pub struct FirmwareChunk {
+    #[n(0)]
+    pub index: u16,
+    #[n(1)]
+    pub data: Vec<u8>,
+}
 
-    pub fn payload(&self) -> &Vec<u8> {
-        &self.payload
-    }
+#[quantum_link]
+pub enum FirmwareUpdateResult {
+    #[n(0)]
+    Success {
+        #[n(0)]
+        installed_version: String,
+    },
+    #[n(1)]
+    Error(#[n(0)] String),
 }
diff --git a/api/src/api/message.rs b/api/src/api/message.rs
index 97390c8..a103eeb 100644
--- a/api/src/api/message.rs
+++ b/api/src/api/message.rs
@@ -1,12 +1,17 @@
 use super::onboarding::OnboardingState;
 use crate::api::raw::RawData;
-use crate::backup::Shard;
+use crate::backup::{
+    BackupShardRequest, BackupShardResponse, RestoreShardRequest, RestoreShardResponse,
+};
 use crate::bitcoin::*;
-use crate::firmware::{FirmwarePayload, FirmwareUpdate};
+use crate::firmware::{
+    FirmwareDownloadRequest, FirmwareDownloadResponse, FirmwareUpdateCheckRequest,
+    FirmwareUpdateCheckResponse, FirmwareUpdateResult,
+};
 use crate::fx::ExchangeRate;
 use crate::pairing::{PairingRequest, PairingResponse};
 use crate::quantum_link::QuantumLink;
-use crate::scv::{SecurityChallengeMessage, SecurityProofMessage};
+use crate::scv::{SecurityChallengeRequest, SecurityChallengeResponse};
 use crate::status::{DeviceStatus, EnvoyStatus};
 use flutter_rust_bridge::frb;
 use minicbor_derive::{Decode, Encode};
@@ -67,31 +72,43 @@ pub enum QuantumLinkMessage {
     #[n(0)]
     ExchangeRate(#[n(0)] ExchangeRate),
     #[n(1)]
-    FirmwareUpdate(#[n(0)] FirmwareUpdate),
+    FirmwareUpdateCheckRequest(#[n(0)] FirmwareUpdateCheckRequest),
     #[n(2)]
-    DeviceStatus(#[n(0)] DeviceStatus),
+    FirmwareUpdateCheckResponse(#[n(0)] FirmwareUpdateCheckResponse),
     #[n(3)]
-    EnvoyStatus(#[n(0)] EnvoyStatus),
+    FirmwareDownloadRequest(#[n(0)] FirmwareDownloadRequest),
     #[n(4)]
-    PairingResponse(#[n(0)] PairingResponse),
+    FirmwareDownloadResponse(#[n(0)] FirmwareDownloadResponse),
     #[n(5)]
-    PairingRequest(#[n(0)] PairingRequest),
+    FirmwareUpdateResult(#[n(0)] FirmwareUpdateResult),
     #[n(6)]
-    OnboardingState(#[n(0)] OnboardingState),
+    DeviceStatus(#[n(0)] DeviceStatus),
     #[n(7)]
-    SignPsbt(#[n(0)] SignPsbt),
+    EnvoyStatus(#[n(0)] EnvoyStatus),
     #[n(8)]
-    AccountUpdate(#[n(0)] AccountUpdate),
+    PairingRequest(#[n(0)] PairingRequest),
     #[n(9)]
-    FirmwarePayload(#[n(0)] FirmwarePayload),
+    PairingResponse(#[n(0)] PairingResponse),
     #[n(10)]
-    BroadcastTransaction(#[n(0)] BroadcastTransaction),
+    OnboardingState(#[n(0)] OnboardingState),
     #[n(11)]
-    SecurityChallengeMessage(#[n(0)] SecurityChallengeMessage),
+    SignPsbt(#[n(0)] SignPsbt),
     #[n(12)]
-    SecurityProofMessage(#[n(0)] SecurityProofMessage),
+    BroadcastTransaction(#[n(0)] BroadcastTransaction),
     #[n(13)]
-    Shard(#[n(0)] Shard),
+    AccountUpdate(#[n(0)] AccountUpdate),
     #[n(14)]
+    SecurityChallengeRequest(#[n(0)] SecurityChallengeRequest),
+    #[n(15)]
+    SecurityChallengeResponse(#[n(0)] SecurityChallengeResponse),
+    #[n(16)]
+    BackupShardRequest(#[n(0)] BackupShardRequest),
+    #[n(17)]
+    BackupShardResponse(#[n(0)] BackupShardResponse),
+    #[n(18)]
+    RestoreShardRequest(#[n(0)] RestoreShardRequest),
+    #[n(19)]
+    RestoreShardResponse(#[n(0)] RestoreShardResponse),
+    #[n(20)]
     RawData(#[n(0)] RawData),
 }
diff --git a/api/src/api/scv.rs b/api/src/api/scv.rs
index 8287e2a..4b361a4 100644
--- a/api/src/api/scv.rs
+++ b/api/src/api/scv.rs
@@ -70,14 +70,14 @@ impl ChallengeResponse {
 }
 
 #[quantum_link]
-pub struct SecurityChallengeMessage {
+pub struct SecurityChallengeRequest {
     #[n(0)]
     pub data: Vec<u8>,
 }
 
-impl SecurityChallengeMessage {
+impl SecurityChallengeRequest {
     pub fn new(data: Vec<u8>) -> Self {
-        SecurityChallengeMessage { data }
+        SecurityChallengeRequest { data }
     }
 
     pub fn data(&self) -> &Vec<u8> {
@@ -86,14 +86,14 @@ impl SecurityChallengeMessage {
 }
 
 #[quantum_link]
-pub struct SecurityProofMessage {
+pub struct SecurityChallengeResponse {
     #[n(0)]
     pub data: Vec<u8>,
 }
 
-impl SecurityProofMessage {
+impl SecurityChallengeResponse {
     pub fn new(data: Vec<u8>) -> Self {
-        SecurityProofMessage { data }
+        SecurityChallengeResponse { data }
     }
 
     pub fn data(&self) -> &Vec<u8> {