diff --git a/apps/machine/src/config/device.ts b/apps/machine/src/config/device.ts
index cffdaa3..9a06c9a 100644
--- a/apps/machine/src/config/device.ts
+++ b/apps/machine/src/config/device.ts
@@ -15,7 +15,15 @@ import type { HalConfig, CassetteConfig } from '@/services/hal'
 /**
  * Supported machine models
  */
-export type MachineModel = 'sintra' | 'tejo' | 'douro' | 'gaia' | 'batm3' | 'custom'
+export type MachineModel =
+  | 'sintra'
+  | 'tejo'
+  | 'douro'
+  | 'gaia'
+  | 'batm3'
+  | 'rpi4'
+  | 'rpi5'
+  | 'custom'
 
 /**
  * Full device configuration
@@ -28,7 +36,10 @@ export interface DeviceConfig {
   /** Bill validator configuration */
   validator: {
     /** Validator protocol type */
-    type: 'id003' | 'ebds'
+    // 'apex' = Pyramid Apex RS-232. The driver landed with the Pi 5 work
+    // (packages/hal ValidatorType) but these app-side unions were never
+    // widened, so no machine could actually be configured to use it.
+    type: 'id003' | 'ebds' | 'apex'
     /** Serial device path(s) */
     device: string | string[]
   }
@@ -117,6 +128,52 @@ export const MACHINE_PRESETS: Record<MachineModel, Omit<DeviceConfig, 'fiatCode'
    * - Dispenser: Fujitsu F56
    * Note: Device paths may vary - verify on hardware
    */
+  /**
+   * Raspberry Pi 4 / CM4 reference build (aarch64).
+   * - Validator: Pyramid Apex 7600 over RS-232, via a USB-serial adapter
+   * - Dispenser: NONE WIRED YET — cash-in only
+   *
+   * The device path is the udev symlink raspberry-pi-4.nix creates for an
+   * FTDI bridge. Swap to ttyValidator1 (CP210x) or ttyValidator2 (CH340) to
+   * match the adapter actually fitted; `ls -l /dev/ttyValidator*` after
+   * plugging it in will say which one appeared.
+   *
+   * The dispenser block is a placeholder, not a claim. DispenserType has no
+   * 'none' variant and DeviceConfig requires the field, so it points at a
+   * path that does not exist and carries no cassettes. Cash-out is not
+   * available on this board until real hardware and a real path land here.
+   */
+  rpi4: {
+    model: 'rpi4',
+    validator: {
+      type: 'apex',
+      device: '/dev/ttyValidator0',
+    },
+    dispenser: {
+      type: 'f56',
+      device: '/dev/ttyDispenser-not-fitted',
+      cassettes: [],
+    },
+  },
+
+  /**
+   * Raspberry Pi 5 reference build (aarch64). Same shape as rpi4 — same
+   * validator, same absent dispenser, same udev symlinks from
+   * raspberry-pi-5.nix.
+   */
+  rpi5: {
+    model: 'rpi5',
+    validator: {
+      type: 'apex',
+      device: '/dev/ttyValidator0',
+    },
+    dispenser: {
+      type: 'f56',
+      device: '/dev/ttyDispenser-not-fitted',
+      cassettes: [],
+    },
+  },
+
   gaia: {
     model: 'gaia',
     validator: {
diff --git a/apps/machine/src/services/hal.ts b/apps/machine/src/services/hal.ts
index f48fda8..4ab83ee 100644
--- a/apps/machine/src/services/hal.ts
+++ b/apps/machine/src/services/hal.ts
@@ -23,7 +23,7 @@ export interface CassetteConfig {
 
 export interface HalConfig {
   validator: {
-    type: 'id003' | 'ebds'
+    type: 'id003' | 'ebds' | 'apex'
     device: string | string[]
     fiatCode: string
   }