diff --git a/src/kaleidoscope/device/keyboardio/Atreus2.cpp b/src/kaleidoscope/device/keyboardio/Atreus2.cpp
index 5a0ad92d..d5eb707f 100644
--- a/src/kaleidoscope/device/keyboardio/Atreus2.cpp
+++ b/src/kaleidoscope/device/keyboardio/Atreus2.cpp
@@ -1,6 +1,6 @@
 /* -*- mode: c++ -*-
  * Keyboardio Atreus hardware support for Kaleidoscope
- * Copyright (C) 2019  Keyboard.io, Inc
+ * Copyright (C) 2019, 2020  Keyboard.io, Inc
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -22,11 +22,49 @@
 #include "kaleidoscope/Runtime.h"
 #include "kaleidoscope/driver/keyscanner/Base_Impl.h"
 
+// We're using the `kaleidoscope::device::keyboardio` namespace, and set up the
+// aliases here, so that they're in the global namespace, within the scope of
+// this file. We do that, because of how templates are resolved and evaluated,
+// see more just down below!
+using namespace kaleidoscope::device::keyboardio;
+using KeyScannerProps = typename AtreusProps::KeyScannerProps;
+using KeyScanner = typename AtreusProps::KeyScanner;
+
 namespace kaleidoscope {
 namespace device {
 namespace keyboardio {
 
-ATMEGA_KEYSCANNER_BOILERPLATE
+// `KeyScannerProps` here refers to the alias set up above. We do not need to
+// prefix the `matrix_rows` and `matrix_columns` names within the array
+// declaration, because those are resolved within the context of the class, so
+// the `matrix_rows` in `KeyScannerProps::matrix_row_pins[matrix_rows]` gets
+// resolved as `KeyScannerProps::matrix_rows`.
+const uint8_t KeyScannerProps::matrix_rows;
+const uint8_t KeyScannerProps::matrix_columns;
+constexpr uint8_t KeyScannerProps::matrix_row_pins[matrix_rows];
+constexpr uint8_t KeyScannerProps::matrix_col_pins[matrix_columns];
+
+// Resolving is a bit different in case of templates, however: the name of the
+// array is resolved within the scope of the namespace and the class, but the
+// array size is not - because it is a template. Therefore, we need a fully
+// qualified name there - or an alias in the global scope, which we set up just
+// above.
+template<> uint16_t KeyScanner::previousKeyState_[KeyScannerProps::matrix_rows] = {};
+template<> uint16_t KeyScanner::keyState_[KeyScannerProps::matrix_rows] = {};
+template<> uint16_t KeyScanner::masks_[KeyScannerProps::matrix_rows] = {};
+template<> uint8_t KeyScanner::debounce_matrix_[KeyScannerProps::matrix_rows][KeyScannerProps::matrix_columns] = {};
+
+// We set up the TIMER1 interrupt vector here. Due to dependency reasons, this
+// cannot be in a header-only driver, and must be placed here.
+//
+// Timer1 is responsible for setting a property on the KeyScanner, which will
+// tell it to do a scan. We use this to make sure that scans happen at roughly
+// the intervals we want. We do the scan outside of the interrupt scope for
+// practical reasons: guarding every codepath against interrupts that can be
+// reached from the scan is far too tedious, for very little gain.
+ISR(TIMER1_OVF_vect) {
+  Runtime.device().keyScanner().do_scan_ = true;
+}
 
 }
 }
diff --git a/src/kaleidoscope/device/keyboardio/Atreus2.h b/src/kaleidoscope/device/keyboardio/Atreus2.h
index db8082c7..5b2659c2 100644
--- a/src/kaleidoscope/device/keyboardio/Atreus2.h
+++ b/src/kaleidoscope/device/keyboardio/Atreus2.h
@@ -29,11 +29,36 @@ namespace kaleidoscope {
 namespace device {
 namespace keyboardio {
 
-ATMEGA32U4_KEYBOARD(
-  Atreus, Caterina, "atreus",
-  ROW_PIN_LIST({PIN_F6, PIN_F5, PIN_F4, PIN_F1}),
-  COL_PIN_LIST({PIN_F7, PIN_E2, PIN_C7, PIN_C6, PIN_B6, PIN_B5, PIN_D7, PIN_D6, PIN_D4, PIN_D5, PIN_D3, PIN_D2})
-);
+
+struct AtreusProps : kaleidoscope::device::ATmega32U4KeyboardProps {
+  struct KeyScannerProps : public kaleidoscope::driver::keyscanner::ATmegaProps {
+
+    static constexpr uint8_t matrix_rows = 4;
+    static constexpr uint8_t matrix_columns = 12;
+    typedef MatrixAddr<matrix_rows, matrix_columns> KeyAddr;
+#ifndef KALEIDOSCOPE_VIRTUAL_BUILD
+    static constexpr uint8_t matrix_row_pins[matrix_rows] =  {PIN_F6, PIN_F5, PIN_F4, PIN_F1};
+    static constexpr uint8_t matrix_col_pins[matrix_columns] = {PIN_F7, PIN_E2, PIN_C7, PIN_C6, PIN_B6, PIN_B5, PIN_D7, PIN_D6, PIN_D4, PIN_D5, PIN_D3, PIN_D2};
+#endif // ifndef KALEIDOSCOPE_VIRTUAL_BUILD
+  };
+
+  typedef kaleidoscope::driver::keyscanner::ATmega<KeyScannerProps> KeyScanner;
+  typedef kaleidoscope::driver::bootloader::avr::Caterina BootLoader;
+  static constexpr const char *short_name = "atreus";
+};
+
+#ifndef KALEIDOSCOPE_VIRTUAL_BUILD
+class Atreus: public kaleidoscope::device::ATmega32U4Keyboard<AtreusProps> {};
+#else // ifndef KALEIDOSCOPE_VIRTUAL_BUILD
+/* Device definition omitted for virtual device builds.
+ * We need to forward declare the device name, though, as there are
+ * some legacy extern references to boards whose definition
+ * depends on this.
+ */
+class Atreus;
+
+#endif // ifndef KALEIDOSCOPE_VIRTUAL_BUILD
+
 
 #define PER_KEY_DATA(dflt,                                                    \
     R0C0, R0C1, R0C2, R0C3, R0C4,             R0C7, R0C8, R0C9, R0C10, R0C11, \