diff --git a/Cargo.lock b/Cargo.lock
index 79427c0..93f2695 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1062,6 +1062,12 @@ version = "1.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1261fe7e33c73b354eab43b1273a57c8f967d0391e80353e51f764ac02cf6775"
 
+[[package]]
+name = "paste"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.15"
@@ -1191,6 +1197,28 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "rmp"
+version = "0.8.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "228ed7c16fa39782c3b3468e974aec2795e9089153cd08ee2e9aefb3613334c4"
+dependencies = [
+ "byteorder",
+ "num-traits",
+ "paste",
+]
+
+[[package]]
+name = "rmp-serde"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52e599a477cf9840e92f2cde9a7189e67b42c57532749bf90aea6ec10facd4db"
+dependencies = [
+ "byteorder",
+ "rmp",
+ "serde",
+]
+
 [[package]]
 name = "rustc-hash"
 version = "2.1.0"
@@ -1242,6 +1270,7 @@ dependencies = [
  "esp-idf-svc",
  "futures",
  "log",
+ "rmp-serde",
  "serde",
  "serde_json",
  "time",
diff --git a/Cargo.toml b/Cargo.toml
index 13d2b4e..bd4ab40 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -32,6 +32,7 @@ futures = "0.3.31"
 serde = { version = "1.0.217", features = ["derive"] }
 serde_json = "1.0.134"
 time = { version = "0.3.37", features = ["std", "serde-human-readable"] }
+rmp-serde = "1.3.0"
 
 [[package.metadata.esp-idf-sys.extra_components]]
 remote_component = { name = "espressif/esp_tinyusb", version = "96cbb5b308f92d2493a0c714f097dcfc51add807", git = "https://github.com/LaunchPlatform/esp-usb.git", path = "device/esp_tinyusb" }
diff --git a/src/api/processor.rs b/src/api/processor.rs
index 4b3423e..9031c1d 100644
--- a/src/api/processor.rs
+++ b/src/api/processor.rs
@@ -95,7 +95,10 @@ impl Processor {
 
     fn list_files(&self, path: &str) -> anyhow::Result<Response> {
         let dir_path = Path::new(&self.root_dir).join(path);
-        log::info!("Listing files at {}", dir_path.to_str().unwrap_or("<Unknown>"));
+        log::info!(
+            "Listing files at {}",
+            dir_path.to_str().unwrap_or("<Unknown>")
+        );
         // Ideally we should find a way to learn the size of all files, but we need to
         // iterate over all files anyway... so.. maybe not? :/
         let mut files: Vec<File> = vec![];
@@ -143,7 +146,8 @@ impl Processor {
         let mut buf = vec![0; chunk_size as usize];
         for offset in (0..file_size).step_by(chunk_size as usize) {
             file.read(&mut buf)?;
-            assert_eq!(file.stream_position().unwrap(), offset);
+            // TODO: somehow stream_position doesn't work correctly?
+            // assert_eq!(file.stream_position().unwrap(), offset);
             send(CommandResponse {
                 id: req_id.to_string(),
                 response: FetchFileChunk {
@@ -216,9 +220,12 @@ pub async fn process_events(
                     Ok(request) => processor.as_mut().unwrap().process(
                         &request,
                         |response: CommandResponse| match response.response {
-                            FetchFileChunk { .. } => {
-                                // TODO:
-                            }
+                            FetchFileChunk { .. } => client
+                                .send(
+                                    FrameType::Binary(false),
+                                    &rmp_serde::to_vec(&response).unwrap(),
+                                )
+                                .unwrap(),
                             _ => client
                                 .send(
                                     FrameType::Text(false),