diff --git a/Cargo.lock b/Cargo.lock
index a35616f..31873e8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -13,9 +13,9 @@ dependencies = [
 
 [[package]]
 name = "autocfg"
-version = "1.3.0"
+version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0c4b4d0bd25bd0b74681c0ad21497610ce1b7c91b1022cd21c80c6fbdd9476b0"
+checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
 
 [[package]]
 name = "bitflags"
@@ -44,31 +44,11 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "67ba02a97a2bd10f4b59b25c7973101c79642302776489e030cd13cdab09ed15"
 
-[[package]]
-name = "const_format"
-version = "0.2.32"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e3a214c7af3d04997541b18d432afaff4c455e79e2029079647e72fc2bd27673"
-dependencies = [
- "const_format_proc_macros",
-]
-
-[[package]]
-name = "const_format_proc_macros"
-version = "0.2.32"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c7f6ff08fd20f4f299298a28e2dfa8a8ba1036e6cd2460ac1de7b425d76f2500"
-dependencies = [
- "proc-macro2",
- "quote",
- "unicode-xid",
-]
-
 [[package]]
 name = "critical-section"
-version = "1.1.2"
+version = "1.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7059fff8937831a9ae6f0fe4d658ffabf58f2ca96aa9dec1c889f936f705f216"
+checksum = "f64009896348fc5af4222e9cf7d7d82a95a256c634ebcf61c53e4ea461422242"
 
 [[package]]
 name = "embedded-io"
@@ -76,6 +56,12 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ef1a6892d9eef45c8fa6b9e0086428a2cca8491aca8f787c534a3d6d0bcb3ced"
 
+[[package]]
+name = "embedded-io"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "edd0f118536f44f5ccd48bcb8b111bdc3de888b58c74639dfb034a357d0f206d"
+
 [[package]]
 name = "file_rpc"
 version = "0.1.0"
@@ -120,9 +106,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.155"
+version = "0.2.159"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "97b3888a4aecf77e811145cadf6eef5901f4782c53886191b2f693f24761847c"
+checksum = "561d97a539a36e26a9a5fad1ea11a3039a67714694aaa379433e580854bc3dc5"
 
 [[package]]
 name = "lock_api"
@@ -159,13 +145,13 @@ dependencies = [
 
 [[package]]
 name = "postcard"
-version = "1.0.8"
+version = "1.0.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a55c51ee6c0db07e68448e336cf8ea4131a620edefebf9893e759b2d793420f8"
+checksum = "5f7f0a8d620d71c457dd1d47df76bb18960378da56af4527aaa10f515eee732e"
 dependencies = [
  "cobs",
- "const_format",
- "embedded-io",
+ "embedded-io 0.4.0",
+ "embedded-io 0.6.1",
  "heapless",
  "postcard-derive",
  "serde",
@@ -173,9 +159,9 @@ dependencies = [
 
 [[package]]
 name = "postcard-derive"
-version = "0.1.1"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fc4b01218787dd4420daf63875163a787a78294ad48a24e9f6fa8c6507759a79"
+checksum = "0239fa9c1d225d4b7eb69925c25c5e082307a141e470573fbbe3a817ce6a7a37"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -184,36 +170,36 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.85"
+version = "1.0.86"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "22244ce15aa966053a896d1accb3a6e68469b97c7f33f284b99f0d576879fc23"
+checksum = "5e719e8df665df0d1c8fbfd238015744736151d4445ec0836b8e628aae103b77"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.36"
+version = "1.0.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0fa76aaf39101c457836aec0ce2316dbdc3ab723cdda1c6bd4e6ad4208acaca7"
+checksum = "b5b9d34b8991d19d98081b46eacdd8eb58c6f2b201139f7c5f643cc155a633af"
 dependencies = [
  "proc-macro2",
 ]
 
 [[package]]
 name = "redox_syscall"
-version = "0.5.1"
+version = "0.5.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "469052894dcb553421e483e4209ee581a45100d31b4018de03e5a7ad86374a7e"
+checksum = "9b6dfecf2c74bce2466cabf93f6664d6998a69eb21e39f4207930065b27b771f"
 dependencies = [
  "bitflags",
 ]
 
 [[package]]
 name = "rustc_version"
-version = "0.4.0"
+version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bfa0f585226d2e68097d4f95d113b15b83a82e819ab25717ec0590d9584ef366"
+checksum = "cfcb3a22ef46e85b45de6ee7e79d063319ebb6594faafcf1c225ea92ab6e9b92"
 dependencies = [
  "semver",
 ]
@@ -232,22 +218,18 @@ checksum = "61697e0a1c7e512e84a621326239844a24d8207b4669b41bc18b32ea5cbf988b"
 
 [[package]]
 name = "serde"
-version = "1.0.203"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7253ab4de971e72fb7be983802300c30b5a7f0c2e56fab8abfc6a214307c0094"
+version = "1.0.210"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.203"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "500cbc0ebeb6f46627f50f3f5811ccf6bf00643be300b4c3eabc0ef55dc5b5ba"
+version = "1.0.210"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.66",
+ "syn 2.0.79",
 ]
 
 [[package]]
@@ -284,9 +266,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.66"
+version = "2.0.79"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c42f3f41a2de00b01c0aaad383c5a45241efc8b2d1eda5661812fda5f3cdcff5"
+checksum = "89132cd0bf050864e1d38dc3bbc07a0eb8e7530af26344d3d2bbbef83499f590"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -330,15 +312,9 @@ dependencies = [
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.12"
+version = "1.0.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
-
-[[package]]
-name = "unicode-xid"
-version = "0.2.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f962df74c8c05a667b5ee8bcf162993134c104e96440b663c8daa176dc772d8c"
+checksum = "e91b56cd4cadaeb79bbf1a5645f6b4f8dc5bde8834ad5894a8db35fda9efa1fe"
 
 [[package]]
 name = "vfs_rpc"
@@ -351,9 +327,9 @@ dependencies = [
 
 [[package]]
 name = "windows-targets"
-version = "0.52.5"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6f0713a46559409d202e70e28227288446bf7841d3211583a4b53e3f6d96e7eb"
+checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
 dependencies = [
  "windows_aarch64_gnullvm",
  "windows_aarch64_msvc",
@@ -367,48 +343,48 @@ dependencies = [
 
 [[package]]
 name = "windows_aarch64_gnullvm"
-version = "0.52.5"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7088eed71e8b8dda258ecc8bac5fb1153c5cffaf2578fc8ff5d61e23578d3263"
+checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"
 
 [[package]]
 name = "windows_aarch64_msvc"
-version = "0.52.5"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9985fd1504e250c615ca5f281c3f7a6da76213ebd5ccc9561496568a2752afb6"
+checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
 
 [[package]]
 name = "windows_i686_gnu"
-version = "0.52.5"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88ba073cf16d5372720ec942a8ccbf61626074c6d4dd2e745299726ce8b89670"
+checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
 
 [[package]]
 name = "windows_i686_gnullvm"
-version = "0.52.5"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "87f4261229030a858f36b459e748ae97545d6f1ec60e5e0d6a3d32e0dc232ee9"
+checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
 
 [[package]]
 name = "windows_i686_msvc"
-version = "0.52.5"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "db3c2bf3d13d5b658be73463284eaf12830ac9a26a90c717b7f771dfe97487bf"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
 
 [[package]]
 name = "windows_x86_64_gnu"
-version = "0.52.5"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4e4246f76bdeff09eb48875a0fd3e2af6aada79d409d33011886d3e1581517d9"
+checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
 
 [[package]]
 name = "windows_x86_64_gnullvm"
-version = "0.52.5"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "852298e482cd67c356ddd9570386e2862b5673c85bd5f88df9ab6802b334c596"
+checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
 
 [[package]]
 name = "windows_x86_64_msvc"
-version = "0.52.5"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bec47e5bfd1bff0eeaf6d8b485cc1074891a197ab4225d504cb7a1ab88b02bf0"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
diff --git a/Cargo.toml b/Cargo.toml
index 9f173c9..23ce8e2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,3 +15,7 @@ vfs_rpc = { version = "0.1.0", path = "../vfs/vfs_rpc" }
 strip = true
 lto = true
 opt-level = "s"
+
+[patch.crates-io]
+serde = { path = "../serde/serde" }
+serde_derive = { path = "../serde/serde_derive" }
diff --git a/src/main.rs b/src/main.rs
index c711554..db2f490 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,5 @@
 use std::{
-    borrow::Cow, fs::File, io::{Read, Seek}, os::mikros::{ipc, syscalls}, path::PathBuf, sync::Arc
+    borrow::Cow, fs::File, io::{Read, Seek}, os::mikros::{ipc, syscalls, Errno}, path::PathBuf, sync::Arc
 };
 
 use parking_lot::RwLock;
@@ -20,8 +20,8 @@ struct Serv {
 }
 
 impl fs_rpc::Server for Serv {
-    fn mount(&self, dev: &std::path::Path) -> Result<u64, ()> {
-        let archive = File::open(dev).map_err(|_| ())?;
+    fn mount(&self, dev: &std::path::Path) -> Result<u64, Errno> {
+        let archive = File::open(dev)?;
         let mut archive = Archive::new(archive);
         let entries = archive
             .entries_with_seek()
@@ -37,7 +37,7 @@ impl fs_rpc::Server for Serv {
         Ok((self.mounts.read().len() - 1) as u64)
     }
 
-    fn open(&self, path: &std::path::Path, mount_id: u64) -> Result<(Option<u64>, u64), ()> {
+    fn open(&self, path: &std::path::Path, mount_id: u64) -> Result<(Option<u64>, u64), Errno> {
         let mounts = self.mounts.read();
         let mount = &mounts[mount_id as usize];
         let (&file_offset, &file_size) = mount
@@ -45,7 +45,7 @@ impl fs_rpc::Server for Serv {
             .iter()
             .find(|(entry_path, _offset, _size)| entry_path == path)
             .map(|(_x, y, z)| (y, z))
-            .ok_or(())?;
+            .ok_or(Errno::ENOENT)?;
         self.files
             .write()
             .push(OpenFile {
@@ -57,14 +57,14 @@ impl fs_rpc::Server for Serv {
         Ok((None, (self.files.read().len() - 1) as u64))
     }
 
-    fn open_dir(&self, _path: &std::path::Path, _mount_id: u64) -> Result<(Option<u64>, u64), ()> {
+    fn open_dir(&self, _path: &std::path::Path, _mount_id: u64) -> Result<(Option<u64>, u64), Errno> {
         // TODO
-        Err(())
+        Err(Errno::ENOSYS)
     }
 }
 
 impl file_rpc::Server for Serv {
-    fn read(&self, fd: u64, len: usize) -> Result<Cow<'_, [u8]>, ()> {
+    fn read(&self, fd: u64, len: usize) -> Result<Cow<'_, [u8]>, Errno> {
         let files = self.files.read();
         let file = &files[fd as usize];
         let read_len = usize::min(len, file.len - (file.pos as usize));
@@ -77,31 +77,31 @@ impl file_rpc::Server for Serv {
             .seek(std::io::SeekFrom::Start(file.file_offset + file.pos))
             .unwrap();
         let mut buf = vec![0; read_len];
-        let read_bytes = (&mount.0).read(&mut buf).map_err(|_| ())?;
+        let read_bytes = (&mount.0).read(&mut buf)?;
         buf.truncate(read_bytes);
         std::mem::drop(files);
         self.files.write()[fd as usize].pos += read_bytes as u64;
         Ok(buf.into())
     }
 
-    fn write(&self, _fd: u64, _data: &[u8]) -> Result<(), ()> {
-        Err(())
+    fn write(&self, _fd: u64, _data: &[u8]) -> Result<(), Errno> {
+        Err(Errno::ENOSYS)
     }
 
-    fn close(&self, _fd: u64) {}
+    fn close(&self, _fd: u64) -> Result<(), Errno> { Ok(()) }
 
-    fn size(&self, fd: u64) -> Option<u64> {
-        Some(self.files.read()[fd as usize].len as u64)
+    fn size(&self, fd: u64) -> Result<u64, Errno> {
+        Ok(self.files.read()[fd as usize].len as u64)
     }
 
-    fn dup(&self, fd: u64) -> Option<u64> {
+    fn dup(&self, fd: u64) -> Result<u64, Errno> {
         let mut files = self.files.write();
         let file = files[fd as usize].clone();
         files.push(file);
-        Some((files.len() - 1) as u64)
+        Ok((files.len() - 1) as u64)
     }
 
-    fn seek(&self, fd: u64, pos: file_rpc::SeekFrom) -> u64{
+    fn seek(&self, fd: u64, pos: file_rpc::SeekFrom) -> Result<u64, Errno> {
         let mut files = self.files.write();
         let file = &mut files[fd as usize];
         match pos {
@@ -126,7 +126,7 @@ impl file_rpc::Server for Serv {
                 }
             },
         };
-        file.pos
+        Ok(file.pos)
     }
 
 }