diff --git a/build.sh b/build.sh
index c675c148..66339e5e 100755
--- a/build.sh
+++ b/build.sh
@@ -72,6 +72,10 @@ pushd loopback-fw
 cargo build --target=thumbv7em-none-eabihf --release
 cargo fmt --check
 popd
+pushd loopback-fw-rtic
+cargo build --target=thumbv7em-none-eabihf --release
+cargo fmt --check
+popd
 popd
 
 # Only build the templates (they will panic at run-time due to the use of todo!)
@@ -105,5 +109,6 @@ cp -r ./.cargo "${OUTPUT_NAME}/"
 cp -r ./tools "${OUTPUT_NAME}/"
 cp ./nrf52-code/puzzle-fw/target/thumbv7em-none-eabihf/release/puzzle-fw "${OUTPUT_NAME}/nrf52-code/boards/dongle-fw/puzzle-fw"
 cp ./nrf52-code/loopback-fw/target/thumbv7em-none-eabihf/release/loopback-fw "${OUTPUT_NAME}/nrf52-code/boards/dongle-fw/loopback-fw"
+cp ./nrf52-code/loopback-fw-rtic/target/thumbv7em-none-eabihf/release/loopback-fw-rtic "${OUTPUT_NAME}/nrf52-code/boards/dongle-fw/loopback-fw-rtic"
 find "${OUTPUT_NAME}" -name target -type d -print0 | xargs -0 rm -rf
 zip -r "${OUTPUT_NAME}.zip" "${OUTPUT_NAME}"
diff --git a/nrf52-code/boards/dk/Cargo.toml b/nrf52-code/boards/dk/Cargo.toml
index 4fc4c4d1..e8d19e94 100644
--- a/nrf52-code/boards/dk/Cargo.toml
+++ b/nrf52-code/boards/dk/Cargo.toml
@@ -18,3 +18,4 @@ hal = { package = "nrf52840-hal", version = "0.18.0" }
 [features]
 advanced = []
 radio = []
+usbd = []
diff --git a/nrf52-code/boards/dk/src/lib.rs b/nrf52-code/boards/dk/src/lib.rs
index 88ac36c8..6c22505a 100644
--- a/nrf52-code/boards/dk/src/lib.rs
+++ b/nrf52-code/boards/dk/src/lib.rs
@@ -17,7 +17,7 @@ use cortex_m_semihosting::debug;
 use embedded_hal::digital::{OutputPin, StatefulOutputPin};
 #[cfg(feature = "advanced")]
 use grounded::uninit::GroundedArrayCell;
-#[cfg(feature = "radio")]
+#[cfg(any(feature = "radio", feature = "usbd"))]
 use grounded::uninit::GroundedCell;
 #[cfg(feature = "radio")]
 pub use hal::ieee802154;
@@ -44,14 +44,18 @@ pub mod peripheral;
 #[cfg(feature = "advanced")]
 pub mod usbd;
 
-#[cfg(feature = "radio")]
+#[cfg(any(feature = "radio", feature = "usbd"))]
 struct ClockSyncWrapper<H, L, LSTAT> {
     clocks: Clocks<H, L, LSTAT>,
 }
 
-#[cfg(feature = "radio")]
+#[cfg(any(feature = "radio", feature = "usbd"))]
 unsafe impl<H, L, LSTAT> Sync for ClockSyncWrapper<H, L, LSTAT> {}
 
+/// Our USB Device
+#[cfg(feature = "usbd")]
+pub type UsbDevice = hal::usbd::Usbd<hal::usbd::UsbPeripheral<'static>>;
+
 /// Components on the board
 pub struct Board {
     /// LEDs
@@ -71,6 +75,9 @@ pub struct Board {
     /// USB control endpoint 0
     #[cfg(feature = "advanced")]
     pub ep0in: Ep0In,
+    /// A configured USB Device
+    #[cfg(feature = "usbd")]
+    pub usbd: UsbDevice,
 }
 
 /// All LEDs on the board
@@ -300,7 +307,7 @@ pub fn init() -> Result<Board, Error> {
     // NOTE: this branch runs at most once
     #[cfg(feature = "advanced")]
     static EP0IN_BUF: GroundedArrayCell<u8, 64> = GroundedArrayCell::const_init();
-    #[cfg(feature = "radio")]
+    #[cfg(any(feature = "radio", feature = "usbd"))]
     // We need the wrapper to make this type Sync, as it contains raw pointers
     static CLOCKS: GroundedCell<
         ClockSyncWrapper<
@@ -317,7 +324,7 @@ pub fn init() -> Result<Board, Error> {
     let clocks = clocks.start_lfclk();
     let _clocks = clocks.enable_ext_hfosc();
     // extend lifetime to `'static`
-    #[cfg(feature = "radio")]
+    #[cfg(any(feature = "radio", feature = "usbd"))]
     let clocks = unsafe {
         let clocks_ptr = CLOCKS.get();
         clocks_ptr.write(ClockSyncWrapper { clocks: _clocks });
@@ -370,6 +377,15 @@ pub fn init() -> Result<Board, Error> {
         radio
     };
 
+    #[cfg(feature = "usbd")]
+    {
+        defmt::debug!("Enabling SOF interrupts...");
+        periph.USBD.inten.modify(|_r, w| {
+            w.sof().set_bit();
+            w
+        });
+    }
+
     Ok(Board {
         leds: Leds {
             _1: Led { inner: led1pin },
@@ -386,6 +402,8 @@ pub fn init() -> Result<Board, Error> {
         power: periph.POWER,
         #[cfg(feature = "advanced")]
         ep0in: unsafe { Ep0In::new(&EP0IN_BUF) },
+        #[cfg(feature = "usbd")]
+        usbd: UsbDevice::new(hal::usbd::UsbPeripheral::new(periph.USBD, clocks)),
     })
 }
 
diff --git a/nrf52-code/loopback-fw-rtic/.cargo/config.toml b/nrf52-code/loopback-fw-rtic/.cargo/config.toml
new file mode 100644
index 00000000..436cc4fb
--- /dev/null
+++ b/nrf52-code/loopback-fw-rtic/.cargo/config.toml
@@ -0,0 +1,23 @@
+[target.thumbv7em-none-eabihf]
+# set custom cargo runner to flash & run on embedded target when we call `cargo run`
+# for more information, check out https://github.com/probe-rs
+runner = [
+  "probe-rs",
+  "run",
+  "--chip",
+  "nRF52840_xxAA",
+  "--allow-erase-all",
+  "--log-format",
+  "{t} {[{L}]%bold} {s} {({c:bold} {fff}:{l:1})%dimmed}"
+]
+# Or use "{[{L}]%bold} {s} {({c:bold} {fff}:{l:1})%dimmed}" to disable timestamps
+
+linker = "flip-link" # adds stack overflow protection
+rustflags = [
+  "-C", "link-arg=-Tlink.x", # use the cortex-m-rt linker script
+  "-C", "link-arg=-Tdefmt.x", # defmt support
+]
+
+[build]
+# cross-compile to this target
+target = "thumbv7em-none-eabihf" # = ARM Cortex-M4 with FPU
diff --git a/nrf52-code/loopback-fw-rtic/.gitignore b/nrf52-code/loopback-fw-rtic/.gitignore
new file mode 100644
index 00000000..eb5a316c
--- /dev/null
+++ b/nrf52-code/loopback-fw-rtic/.gitignore
@@ -0,0 +1 @@
+target
diff --git a/nrf52-code/loopback-fw-rtic/Cargo.lock b/nrf52-code/loopback-fw-rtic/Cargo.lock
new file mode 100644
index 00000000..881e4ec4
--- /dev/null
+++ b/nrf52-code/loopback-fw-rtic/Cargo.lock
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+ "rtic-core",
+ "rtic-macros",
+]
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+ "embedded-hal-async",
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+ "portable-atomic",
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diff --git a/nrf52-code/loopback-fw-rtic/Cargo.toml b/nrf52-code/loopback-fw-rtic/Cargo.toml
new file mode 100644
index 00000000..eddb7d51
--- /dev/null
+++ b/nrf52-code/loopback-fw-rtic/Cargo.toml
@@ -0,0 +1,16 @@
+[package]
+authors = ["Ferrous Systems"]
+edition = "2021"
+license = "MIT OR Apache-2.0"
+name = "loopback-fw-rtic"
+version = "0.0.0"
+
+[dependencies]
+consts = { version = "0.1.0", path = "../consts" }
+defmt = "0.3.10"
+defmt-rtt = "0.4.1"
+dk = { version = "0.0.0", path = "../boards/dk", features = ["usbd"] }
+rtic = { version = "2.1.2", features = ["thumbv7-backend"] }
+rtic-monotonics = { version = "2.0.3", features = ["cortex-m-systick"] }
+usb-device = { version = "0.3.2", features = ["defmt"] }
+usbd-serial = "0.2.2"
diff --git a/nrf52-code/loopback-fw-rtic/src/main.rs b/nrf52-code/loopback-fw-rtic/src/main.rs
new file mode 100644
index 00000000..acd2aaf7
--- /dev/null
+++ b/nrf52-code/loopback-fw-rtic/src/main.rs
@@ -0,0 +1,113 @@
+//! The Loopback Firmware, written using RTIC
+//!
+//! Currently this runs on the Developer Kit and not the Dongle, because it's
+//! easier to debug.
+//!
+//! And it doesn't do any radio stuff - just USB Serial.
+
+#![no_main]
+#![no_std]
+
+use defmt_rtt as _;
+
+#[rtic::app(device = dk, peripherals = false)]
+mod app {
+    use core::mem::MaybeUninit;
+    use rtic_monotonics::systick::prelude::*;
+
+    systick_monotonic!(Mono, 100);
+
+    #[local]
+    struct MyLocalResources {}
+
+    #[shared]
+    struct MySharedResources {
+        usb_serial: usbd_serial::SerialPort<'static, dk::UsbDevice>,
+        usb_device: usb_device::device::UsbDevice<'static, dk::UsbDevice>,
+    }
+
+    #[init(local = [
+        usb_alloc: MaybeUninit<usb_device::bus::UsbBusAllocator<dk::UsbDevice>> = MaybeUninit::uninit()
+    ])]
+    fn init(cx: init::Context) -> (MySharedResources, MyLocalResources) {
+        let board = dk::init().unwrap();
+        Mono::start(cx.core.SYST, 64_000_000);
+
+        defmt::debug!("Building USB allocator...");
+        let usb_alloc = cx
+            .local
+            .usb_alloc
+            .write(usb_device::bus::UsbBusAllocator::new(board.usbd));
+
+        defmt::debug!("Creating usb_serial...");
+        let usb_serial = usbd_serial::SerialPort::new(usb_alloc);
+
+        defmt::debug!("Building USB Strings...");
+        let strings = usb_device::device::StringDescriptors::new(usb_device::LangID::EN)
+            .manufacturer("Ferrous Systems")
+            .product("Test Device");
+
+        defmt::debug!("Building VID and PID...");
+        let vid_pid =
+            usb_device::device::UsbVidPid(consts::USB_VID_DEMO, consts::USB_PID_DONGLE_LOOPBACK);
+
+        defmt::debug!("Building USB Device...");
+        let usb_device = usb_device::device::UsbDeviceBuilder::new(usb_alloc, vid_pid)
+            .composite_with_iads()
+            .strings(&[strings])
+            .expect("Adding strings")
+            .max_packet_size_0(64)
+            .expect("set_packet_size")
+            .build();
+
+        defmt::debug!("Spawning task...");
+        foo::spawn().ok();
+
+        defmt::debug!("Building structures...");
+        let shared = MySharedResources {
+            usb_serial,
+            usb_device,
+        };
+        let local = MyLocalResources {};
+
+        defmt::debug!("Init Complete!");
+
+        (shared, local)
+    }
+
+    #[task(shared = [usb_serial])]
+    async fn foo(mut cx: foo::Context) {
+        loop {
+            defmt::info!("hello from foo");
+            let _ = cx.shared.usb_serial.lock(|usb_serial| {
+                usb_serial.write(b"Boopity boop");
+            });
+            Mono::delay(1000.millis()).await;
+        }
+    }
+
+    /// USB Interrupt Handler
+    ///
+    /// USB Device is set to fire this whenever there's a Start of Frame from
+    /// the USB Host.
+    #[task(binds = USBD, shared = [usb_serial, usb_device])]
+    fn usb_isr(cx: usb_isr::Context) {
+        (cx.shared.usb_serial, cx.shared.usb_device).lock(|usb_serial, usb_device| {
+            usb_device.poll(&mut [usb_serial]);
+        });
+    }
+}
+
+#[panic_handler]
+fn panic(info: &core::panic::PanicInfo) -> ! {
+    if let Some(location) = info.location() {
+        defmt::error!("Panic at {}:{}", location.file(), location.line());
+    } else {
+        defmt::error!("Panic at unknown location");
+    }
+    loop {
+        core::hint::spin_loop();
+    }
+}
+
+defmt::timestamp!("{=u64:tus}", dk::uptime_us());