diff --git a/gpio-mailbox/Makefile b/gpio-mailbox/Makefile
index bd29573..8d997a1 100644
--- a/gpio-mailbox/Makefile
+++ b/gpio-mailbox/Makefile
@@ -40,9 +40,7 @@
 else ifeq ($(BR2_TARGET_GENERIC_PLATFORM_NAME),gfch100)
   CFLAGS += -DGFCH100
 else ifeq ($(BR2_TARGET_GENERIC_PLATFORM_NAME),gfrg240)
-  # stub out gpio mailbox on gfrg240
-  CFLAGS += -DSTUB
-  LDFLAGS += -lm
+  CFLAGS += -DGFRG240
 else ifeq ($(BR2_TARGET_GENERIC_PLATFORM_NAME),kvm)
   CFLAGS += -DSTUB
   LDFLAGS += -lm
diff --git a/gpio-mailbox/gfrg240.c b/gpio-mailbox/gfrg240.c
new file mode 100644
index 0000000..478953d
--- /dev/null
+++ b/gpio-mailbox/gfrg240.c
@@ -0,0 +1,133 @@
+#ifdef GFRG240
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "fileops.h"
+#include "pin.h"
+
+struct PinHandle_s {
+  int   unused;
+};
+
+struct systemp {
+  const char* value_path;
+};
+
+struct sysgpio {
+  const char* value_path;
+};
+
+struct platform_info {
+  const char *name;
+  struct systemp temp_cpu;
+  struct sysgpio led_red;
+  struct sysgpio led_activity;
+};
+
+struct platform_info platforms[] = {
+  {
+    .name = "GFRG240",
+    .temp_cpu = {
+      .value_path = "/sys/class/hwmon/hwmon0/temp1_input",
+    },
+    .led_red = {
+      .value_path = "/sys/class/leds/pca955x:1/brightness",
+    },
+    .led_activity = {
+      .value_path = "/sys/class/leds/pca955x:0/brightness",
+    },
+  }
+};
+
+struct platform_info *platform = &platforms[0];
+
+// Write the given sysfile
+static void set_sysfile(const char* s, int level) {
+  write_file_int(s, NULL, level);
+}
+
+// Read the given sysfile pin
+static int get_sysfile(const char* s) {
+  return read_file_long(s);
+}
+
+/* standard API follows */
+
+PinHandle PinCreate(void) {
+  PinHandle handle = (PinHandle) calloc(1, sizeof (*handle));
+  if (handle == NULL) {
+    perror("calloc(PinHandle)");
+    return NULL;
+  }
+  return handle;
+}
+
+void PinDestroy(PinHandle handle) {
+  if (handle == NULL)
+    return;
+
+  free(handle);
+}
+
+int PinIsPresent(PinHandle handle, PinId id) {
+  if (handle == NULL) return PIN_ERROR;
+  switch (id) {
+    case PIN_LED_RED:
+    case PIN_LED_ACTIVITY:
+    case PIN_TEMP_CPU:
+      return 1;
+
+    default:
+      return 0;
+  }
+  return 0;
+}
+
+PinStatus PinValue(PinHandle handle, PinId id, int* valueP) {
+  if (handle == NULL) return PIN_ERROR;
+  switch (id) {
+    case PIN_LED_RED:
+      *valueP = get_sysfile(platform->led_red.value_path);
+      break;
+    case PIN_LED_ACTIVITY:
+      *valueP = get_sysfile(platform->led_activity.value_path);
+      break;
+    case PIN_TEMP_CPU:
+      *valueP = get_sysfile(platform->temp_cpu.value_path);
+      break;
+
+    default:
+      *valueP = -1;
+      return PIN_ERROR;
+  }
+  return PIN_OKAY;
+}
+
+PinStatus PinSetValue(PinHandle handle, PinId id, int value) {
+  int scaled;
+
+  if (handle == NULL) return PIN_ERROR;
+
+  /*
+   * gfrg240 led brightness control range is 0-255, value comes in 0-100.
+   * scale value up 2.5x so that we get the full brightness range.
+   */
+  scaled = (value * 25) / 10;
+  switch (id) {
+    case PIN_LED_RED:
+      set_sysfile(platform->led_red.value_path, scaled);
+      break;
+    case PIN_LED_ACTIVITY:
+      set_sysfile(platform->led_activity.value_path, scaled);
+      break;
+    default:
+      return PIN_ERROR;
+  }
+  return PIN_OKAY;
+}
+#endif /* GFRG240 */