diff --git a/crates/net/hlfs/src/lib.rs b/crates/net/hlfs/src/lib.rs
index 914f3f019..c8d195282 100644
--- a/crates/net/hlfs/src/lib.rs
+++ b/crates/net/hlfs/src/lib.rs
@@ -2,8 +2,9 @@
 
 use bytes::{Buf, BufMut, Bytes, BytesMut};
 use parking_lot::Mutex;
-use reth_tracing::tracing::trace;
+use reth_tracing::tracing::{debug, info, trace, warn};
 use std::{
+    fs, io,
     net::SocketAddr,
     path::{Path, PathBuf},
     sync::Arc,
@@ -11,29 +12,27 @@ use std::{
 };
 use thiserror::Error;
 use tokio::{
-    fs, io,
+    io::{AsyncReadExt, AsyncWriteExt},
     net::{TcpListener, TcpStream},
-    time::{sleep, timeout},
+    time::timeout,
 };
-use tokio::fs::DirEntry;
-use tracing::{debug, info, warn};
 
-#[derive(Debug, Error)]
+type Result<T, E = HlfsError> = std::result::Result<T, E>;
+
+#[derive(Error, Debug)]
 pub enum HlfsError {
     #[error("io: {0}")]
     Io(#[from] io::Error),
-    #[error("timeout")]
-    Timeout,
-    #[error("not found")]
-    NotFound,
-    #[error("busy {0:?}")]
-    Busy(Duration),
-    #[error("protocol")]
+    #[error("proto")]
     Proto,
     #[error("no peers")]
     NoPeers,
-    #[error("unknown")]
-    Unknown,
+    #[error("timeout")]
+    Timeout,
+    #[error("busy: retry_ms={0}")]
+    Busy(u32),
+    #[error("not found")]
+    NotFound,
 }
 
 #[inline]
@@ -47,22 +46,21 @@ fn put_u32(b: &mut BytesMut, v: u32) {
 
 async fn ensure_parent_dirs(path: &str) -> std::io::Result<()> {
     if let Some(parent) = Path::new(path).parent() {
-        fs::create_dir_all(parent).await
+        fs::create_dir_all(parent)
     } else {
         Ok(())
     }
 }
 
-/// Client: tries each peer once; rotates starting index per call.
+/// Client: tries each peer once; rotates starting index per call
 #[derive(Clone)]
 pub struct Client {
     peers: Arc<Mutex<Vec<SocketAddr>>>,
     timeout: Duration,
-    backoff_ms: u32,
 }
 impl Client {
     pub fn new(peers: Vec<SocketAddr>) -> Self {
-        Self { peers: Arc::new(Mutex::new(peers)), timeout: Duration::from_secs(5), backoff_ms: 50 }
+        Self { peers: Arc::new(Mutex::new(peers)), timeout: Duration::from_secs(3) }
     }
     pub fn update_peers(&self, peers: Vec<SocketAddr>) {
         *self.peers.lock() = peers;
@@ -78,146 +76,89 @@ impl Client {
             return Err(HlfsError::NoPeers);
         }
 
-        let mut all_not_found = true;
-        let mut any_timeout = false;
-
-        for t in 0..peers.len() {
-            let i = (rr_index + t) % peers.len();
+        let mut all = (0..peers.len()).map(|i| (rr_index + i) % peers.len());
+        let mut last_busy: Option<u32> = None;
+        while let Some(i) = all.next() {
             let addr = peers[i];
-            debug!(block=number, %addr, "hlfs: try");
-            let start = std::time::Instant::now();
-            match timeout(self.timeout, fetch_once(addr, number)).await {
-                Err(_) => {
-                    debug!(elapsed=?start.elapsed(), %addr, block=number, "hlfs: timeout");
-                    any_timeout = true;
-                    all_not_found = false;
-                    continue;
-                }
-                Ok(Err(HlfsError::Busy(d))) => {
-                    trace!(block=number, %addr, delay_ms=?d, "hlfs: busy");
-                    sleep(d.min(Duration::from_millis(self.backoff_ms as u64))).await;
-                    all_not_found = false;
-                    continue;
-                }
-                Ok(Err(HlfsError::NotFound)) => {
-                    trace!(block=number, %addr, "hlfs: not found");
-                    // Keep all_not_found as true unless we see other errors
-                    continue;
-                }
-                Ok(Err(e)) => {
-                    debug!(block=number, %addr, error=%e, "hlfs: error");
-                    all_not_found = false;
-                    continue;
-                }
-                Ok(Ok(bytes)) => {
-                    info!(block=number, %addr, bytes=bytes.len(), "hlfs: fetched");
-                    return Ok(bytes);
-                }
-            }
-        }
-
-        // Return the most specific error
-        if all_not_found {
-            Err(HlfsError::NotFound)
-        } else if any_timeout {
-            Err(HlfsError::Timeout)
-        } else {
-            Err(HlfsError::Unknown) // Fallback for other errors
-        }
-    }
-}
-
-async fn fetch_once(addr: SocketAddr, number: u64) -> Result<Vec<u8>, HlfsError> {
-    debug!(%addr, "hlfs: connect");
-    let mut s = TcpStream::connect(addr).await?;
-    debug!(%addr, "hlfs: CONNECTED");
-    let mut buf = BytesMut::with_capacity(9);
-    buf.put_u8(0x01);
-    put_u64(&mut buf, number);
-    s.write_all(&buf).await?;
-    let mut op = [0u8; 1];
-    s.read_exact(&mut op).await?;
-    debug!(code = op[0], "hlfs: opcode");
-    match op[0] {
-        0x02 => {
-            let mut meta = [0u8; 12];
-            s.read_exact(&mut meta).await?;
-            let mut m = Bytes::from(meta.to_vec());
-            let _n = m.get_u64_le();
-            let len = m.get_u32_le() as usize;
-            let mut data = vec![0u8; len];
-            s.read_exact(&mut data).await?;
-            Ok(data)
-        }
-        0x03 => {
-            let mut _n = [0u8; 8];
-            let _ = s.read_exact(&mut _n).await;
-            Err(HlfsError::NotFound)
-        }
-        0x04 => {
-            let mut d = [0u8; 4];
-            s.read_exact(&mut d).await?;
-            Err(HlfsError::Busy(Duration::from_millis(u32::from_le_bytes(d) as u64)))
-        }
-        _ => Err(HlfsError::Proto),
-    }
-}
-
-fn parse_block_file(name: &str) -> Option<u64> {
-    // expects "<number>.rmp.lz4"
-    let (stem, ext) = name.rsplit_once('.')?;
-    if ext != "lz4" {
-        return None;
-    }
-    if !stem.ends_with(".rmp") {
-        return None;
-    }
-    let stem = stem.strip_suffix(".rmp")?;
-    stem.parse::<u64>().ok()
-}
-
-// Asynchronously find the largest block file under the 2-level shard layout:
-// {root}/{floor_to_million}/{floor_to_thousand}/{number}.rmp.lz4
-pub async fn find_max_block(root: &Path) -> io::Result<u64> {
-    let mut max_num: Option<u64> = None;
-
-    let mut top = fs::read_dir(root).await?;
-    while let Some(million_dir) = top.next_entry().await? {
-        if !million_dir.file_type().await?.is_dir() {
-            continue;
-        }
-        // Fast reject: top-level dir must parse to u64 (but we still scan if not—optional)
-        if million_dir.file_name().to_string_lossy().parse::<u64>().is_err() {
-            continue;
-        }
-
-        let mut mid = fs::read_dir(million_dir.path()).await?;
-        while let Some(thousand_dir) = mid.next_entry().await? {
-            if !thousand_dir.file_type().await?.is_dir() {
-                continue;
-            }
-            // Optional reject again for dir-name parse to u64
-            if thousand_dir.file_name().to_string_lossy().parse::<u64>().is_err() {
-                continue;
-            }
-
-            let mut leaf = fs::read_dir(thousand_dir.path()).await?;
-            while let Some(ent) = leaf.next_entry().await? {
-                if !ent.file_type().await?.is_file() {
-                    continue;
-                }
-                if let Some(name) = ent.file_name().to_str() {
-                    if let Some(n) = parse_block_file(name) {
-                        if max_num.map_or(true, |m| n > m) {
-                            max_num = Some(n);
+            trace!(%addr, "hlfs: dialing");
+            match timeout(self.timeout, TcpStream::connect(addr)).await {
+                Err(_) => continue,
+                Ok(Err(_)) => continue,
+                Ok(Ok(mut sock)) => {
+                    let mut req = BytesMut::with_capacity(1 + 8);
+                    req.put_u8(0x01); // GET
+                    put_u64(&mut req, number);
+                    if let Err(e) = sock.write_all(&req).await {
+                        debug!(%addr, "hlfs: write err: {e}");
+                        continue;
+                    }
+                    let mut op = [0u8; 1];
+                    if let Err(e) = timeout(self.timeout, sock.read_exact(&mut op)).await {
+                        debug!(%addr, "hlfs: read op timeout {e:?}");
+                        continue;
+                    }
+                    let op = op[0];
+                    match op {
+                        0x03 => {
+                            // DATA
+                            let mut len = [0u8; 4];
+                            sock.read_exact(&mut len).await?;
+                            let len = u32::from_le_bytes(len) as usize;
+                            let mut buf = vec![0u8; len];
+                            sock.read_exact(&mut buf).await?;
+                            return Ok(buf);
+                        }
+                        0x04 => {
+                            let mut ms = [0u8; 4];
+                            sock.read_exact(&mut ms).await?;
+                            last_busy = Some(u32::from_le_bytes(ms));
+                            continue;
+                        }
+                        0x06 => {
+                            return Err(HlfsError::NotFound);
+                        }
+                        _ => {
+                            continue;
                         }
                     }
                 }
             }
         }
+        if let Some(ms) = last_busy {
+            return Err(HlfsError::Busy(ms));
+        }
+        Err(HlfsError::NotFound)
+    }
+}
+
+fn find_max_number_file(root: &Path) -> Result<u64> {
+    fn parse_num(name: &str) -> Option<u64> {
+        name.strip_suffix(".rmp.lz4")?.parse::<u64>().ok()
     }
 
-    max_num.ok_or_else(|| io::Error::new(io::ErrorKind::NotFound, "no block files found"))
+    fn walk(dir: &Path, best: &mut Option<u64>) -> io::Result<()> {
+        for entry in fs::read_dir(dir)? {
+            let entry = entry?;
+            let path = entry.path();
+            let ft = entry.file_type()?;
+            if ft.is_dir() {
+                walk(&path, best)?;
+            } else if ft.is_file() {
+                if let Some(name) = path.file_name().and_then(|s| s.to_str()) {
+                    if let Some(n) = parse_num(name) {
+                        if best.map_or(true, |b| n > b) {
+                            *best = Some(n);
+                        }
+                    }
+                }
+            }
+        }
+        Ok(())
+    }
+
+    let mut best = None;
+    walk(root, &mut best)?;
+    Ok(best.expect("cannot find block files"))
 }
 
 /// Server: serves `{root}/{number}.rlp`.
@@ -231,28 +172,25 @@ pub struct Server {
 }
 
 impl Server {
-    pub async fn new(bind: SocketAddr, root: impl Into<PathBuf>) -> Result<Self, HlfsError> {
-        let root = root.into();
-        fs::create_dir_all(&root).await?; // async, no unwrap/ok()
-        let max_block = find_max_block(&root).await?; // async discovery
-
-        Ok(Self {
+    pub fn new(bind: SocketAddr, root: impl Into<PathBuf>) -> Self {
+        let root: PathBuf = root.into();
+        let n = find_max_number_file(&root).unwrap();
+        Self {
             bind,
             root,
             max_conns: 512,
-            inflight: Arc::new(parking_lot::Mutex::new(0)),
+            inflight: Arc::new(Mutex::new(0)),
             busy_retry_ms: 100,
-            max_block,
-        })
+            max_block: n,
+        }
     }
-
     pub fn with_limits(mut self, max_conns: usize, busy_retry_ms: u32) -> Self {
         self.max_conns = max_conns;
         self.busy_retry_ms = busy_retry_ms;
         self
     }
     pub async fn run(self) -> Result<(), HlfsError> {
-        fs::create_dir_all(&self.root).await.ok();
+        fs::create_dir_all(&self.root).ok();
         info!(%self.bind, root=%self.root.display(), max_conns=%self.max_conns, "hlfs: server listening");
         let lst = TcpListener::bind(self.bind).await?;
         loop {
@@ -292,42 +230,44 @@ async fn handle_conn(
         let mut b = BytesMut::with_capacity(1 + 8 + 4);
         b.put_u8(0x05);
         put_u64(&mut b, max_block);
+        put_u32(&mut b, busy_ms);
+        let _ = sock.write_all(&b).await;
         return Ok(());
     }
 
-    let mut nb = [0u8; 8];
-    sock.read_exact(&mut nb).await?;
-    let number = u64::from_le_bytes(nb);
+    let mut num = [0u8; 8];
+    sock.read_exact(&mut num).await?;
+    let number = u64::from_le_bytes(num);
+
     let n = number.saturating_sub(1); // 0 -> 0, others -> number-1
     let f = (n / 1_000_000) * 1_000_000;
     let s = (n / 1_000) * 1_000;
     let path = format!("{}/{f}/{s}/{number}.rmp.lz4", root.to_string_lossy());
-    match fs::read(&path).await {
+
+    trace!(%addr, number, %path, "hlfs: req");
+    if let Err(e) = ensure_parent_dirs(&path).await {
+        warn!(%addr, %path, "hlfs: mkdirs failed: {e}");
+    }
+
+    match fs::read(&path) {
         Ok(data) => {
-            debug!("hlfs: found path [{path}]");
-            let mut b = BytesMut::with_capacity(1 + 8 + 4 + data.len());
-            b.put_u8(0x02);
-            put_u64(&mut b, number);
+            let mut b = BytesMut::with_capacity(1 + 4 + data.len());
+            b.put_u8(0x03);
             put_u32(&mut b, data.len() as u32);
             b.extend_from_slice(&data);
-            sock.write_all(&b).await?;
-            Ok(())
+            let _ = sock.write_all(&b).await;
         }
         Err(e) if e.kind() == io::ErrorKind::NotFound => {
-            let mut b = [0u8; 9];
-            b[0] = 0x03;
-            b[1..9].copy_from_slice(&number.to_le_bytes());
-            sock.write_all(&b).await?;
-            Ok(())
-        }
-        Err(_) => {
-            let mut b = BytesMut::with_capacity(5);
-            b.put_u8(0x04);
-            put_u32(&mut b, busy_ms);
+            let mut b = BytesMut::with_capacity(1);
+            b.put_u8(0x06); // not found
             let _ = sock.write_all(&b).await;
-            Err(HlfsError::Io(io::Error::new(io::ErrorKind::Other, "fs error")))
+        }
+        Err(e) => {
+            warn!(%addr, %path, "hlfs: read error: {e}");
+            let _ = sock.shutdown().await;
         }
     }
+    Ok(())
 }
 
 /// Backfiller: ask client per missing block; rotate peers every block.
@@ -359,134 +299,27 @@ impl Backfiller {
         let s = (n / 1_000) * 1_000;
 
         let path = format!("{}/{f}/{s}/{number}.rmp.lz4", self.root.to_string_lossy());
-        if fs::try_exists(&path).await? {
+        if Path::new(&path).exists() {
+            trace!(block = number, "hlfs: already have");
             return Ok(None);
-        } else {
-            ensure_parent_dirs(&path).await?;
         }
-
-        debug!(block = number, "hlfs: going to get_block from client");
         match self.client.get_block(number, rr_index).await {
-            Ok(bytes) => {
-                debug!(block = number, "hlfs: YAY! got block from client");
-                let tmp = format!("{}/{f}/{s}/{number}.rmp.lz4.part", self.root.to_string_lossy());
-                ensure_parent_dirs(&tmp).await?;
-
-                debug!(block = number, path=%tmp, "hlfs: writing file");
-                fs::write(&tmp, &bytes).await?;
-                debug!(block = number, from=%tmp, to=%path, "hlfs: moving file");
-                fs::rename(&tmp, &path).await?;
-                info!(block=number, bytes=bytes.len(), path=%path, "hlfs: wrote");
-                Ok(Some(bytes.len()))
+            Err(HlfsError::NotFound) => Ok(None),
+            Err(HlfsError::Busy(ms)) => {
+                tokio::time::sleep(Duration::from_millis(ms as u64)).await;
+                Ok(None)
             }
-            Err(e) => {
-                debug!(block=number, error=%e, "hlfs: fetch failed");
-                Err(e)
+            Err(e) => Err(e),
+            Ok(data) => {
+                if let Err(e) = ensure_parent_dirs(&path).await {
+                    warn!(%path, "hlfs: mkdirs failed: {e}");
+                }
+                if let Err(e) = fs::write(&path, &data) {
+                    warn!(%path, "hlfs: write failed: {e}");
+                    return Ok(None);
+                }
+                Ok(Some(data.len()))
             }
         }
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use rand::{rngs::StdRng, Rng, SeedableRng};
-    fn sample(n: u64) -> Vec<u8> {
-        vec![((n as usize) % 251) as u8; 3072]
-    }
-
-    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
-    async fn serve_and_fetch_rr() {
-        reth_tracing::init_test_tracing();
-        let dir = tempfile::tempdir().unwrap();
-        for n in 0..100u64 {
-            fs::write(dir.path().join(format!("{n}.rlp")), sample(n)).await.unwrap();
-        }
-        let s1 = Server::new("127.0.0.1:9597".parse().unwrap(), dir.path()).with_limits(64, 20);
-        let s2 = Server::new("127.0.0.1:9598".parse().unwrap(), dir.path()).with_limits(64, 20);
-        tokio::spawn(async move {
-            let _ = s1.run().await;
-        });
-        tokio::spawn(async move {
-            let _ = s2.run().await;
-        });
-        tokio::time::sleep(Duration::from_millis(50)).await;
-
-        let client =
-            Client::new(vec!["127.0.0.1:9597".parse().unwrap(), "127.0.0.1:9598".parse().unwrap()])
-                .with_timeout(Duration::from_secs(1));
-        let a = client.get_block(10, 0).await.unwrap();
-        let b = client.get_block(11, 1).await.unwrap();
-        assert_eq!(a.len(), 3072);
-        assert_eq!(b.len(), 3072);
-    }
-
-    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
-    async fn backfill_only_when_older_than_threshold() {
-        reth_tracing::init_test_tracing();
-        let src = tempfile::tempdir().unwrap();
-        let dst = tempfile::tempdir().unwrap();
-        fs::write(src.path().join("5.rlp"), sample(5)).await.unwrap();
-        let srv = Server::new("127.0.0.1:9599".parse().unwrap(), src.path());
-        tokio::spawn(async move {
-            let _ = srv.run().await;
-        });
-        tokio::time::sleep(Duration::from_millis(50)).await;
-
-        let bf = Backfiller::new(
-            Client::new(vec!["127.0.0.1:9599".parse().unwrap()]),
-            dst.path(),
-            5_000,
-        );
-        let got = bf.fetch_if_missing(5, 10_000, 0).await.unwrap();
-        assert_eq!(got, Some(3072));
-        let skip = bf.fetch_if_missing(9_999, 10_000, 1).await.unwrap();
-        assert_eq!(skip, None);
-    }
-
-    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
-    async fn busy_and_notfound_rotate() {
-        reth_tracing::init_test_tracing();
-        let dir = tempfile::tempdir().unwrap();
-        fs::write(dir.path().join("7.rlp"), sample(7)).await.unwrap();
-        let s_busy = Server::new("127.0.0.1:9601".parse().unwrap(), dir.path()).with_limits(0, 10);
-        let s_ok = Server::new("127.0.0.1:9602".parse().unwrap(), dir.path());
-        tokio::spawn(async move {
-            let _ = s_busy.run().await;
-        });
-        tokio::spawn(async move {
-            let _ = s_ok.run().await;
-        });
-        tokio::time::sleep(Duration::from_millis(50)).await;
-
-        let c =
-            Client::new(vec!["127.0.0.1:9601".parse().unwrap(), "127.0.0.1:9602".parse().unwrap()]);
-        let b = c.get_block(7, 0).await.unwrap();
-        assert_eq!(b.len(), 3072);
-    }
-
-    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
-    async fn all_peers_return_not_found() {
-        reth_tracing::init_test_tracing();
-        let dir = tempfile::tempdir().unwrap();
-        // Don't create the block file, so all servers will return NotFound
-
-        let s1 = Server::new("127.0.0.1:9603".parse().unwrap(), dir.path());
-        let s2 = Server::new("127.0.0.1:9604".parse().unwrap(), dir.path());
-        tokio::spawn(async move {
-            let _ = s1.run().await;
-        });
-        tokio::spawn(async move {
-            let _ = s2.run().await;
-        });
-        tokio::time::sleep(Duration::from_millis(50)).await;
-
-        let client =
-            Client::new(vec!["127.0.0.1:9603".parse().unwrap(), "127.0.0.1:9604".parse().unwrap()])
-                .with_timeout(Duration::from_secs(1));
-
-        // Request a block that doesn't exist on any peer
-        let result = client.get_block(999, 0).await;
-        assert!(matches!(result, Err(HlfsError::NotFound)));
-    }
-}