diff --git a/Documentation/os/drivers/special/mtd/index.rst b/Documentation/os/drivers/special/mtd/index.rst
index 138a97e8634..e08beac8d78 100644
--- a/Documentation/os/drivers/special/mtd/index.rst
+++ b/Documentation/os/drivers/special/mtd/index.rst
@@ -312,3 +312,18 @@ NuttX provides support for the following MTD devices.
   :glob:
 
   devices/*
+
+RAMTRON SPI FRAM byte writes
+===========================
+
+With ``CONFIG_MTD_RAMTRON`` and ``CONFIG_MTD_BYTE_WRITE`` enabled, the
+RAMTRON driver implements ``MTD_WRITE()`` for arbitrary byte offsets and
+lengths. Writes need not align to the emulated block or erase geometry.
+The callback returns the number of bytes written; requests outside the
+physical device return ``-EINVAL``. A zero-length request within the
+device, including its end offset, returns zero without SPI traffic.
+
+When ``CONFIG_RAMTRON_CHUNKING`` is enabled, writes to parts marked as
+chunk-limited are split at their write-buffer boundaries. Each transfer
+has its own write-enable and write-command sequence. Existing block-write
+operations are unchanged.
diff --git a/drivers/mtd/ramtron.c b/drivers/mtd/ramtron.c
index 7045c561fab..4d26fd7ead9 100644
--- a/drivers/mtd/ramtron.c
+++ b/drivers/mtd/ramtron.c
@@ -431,6 +431,10 @@ static ssize_t ramtron_read(FAR struct mtd_dev_s *dev,
                             off_t offset,
                             size_t nbytes,
                             FAR uint8_t *buffer);
+#ifdef CONFIG_MTD_BYTE_WRITE
+static ssize_t ramtron_write(FAR struct mtd_dev_s *dev, off_t offset,
+                             size_t nbytes, FAR const uint8_t *buffer);
+#endif
 static int ramtron_ioctl(FAR struct mtd_dev_s *dev,
                          int cmd,
                          unsigned long arg);
@@ -844,6 +848,71 @@ static ssize_t ramtron_read(FAR struct mtd_dev_s *dev,
   return nbytes;
 }
 
+/****************************************************************************
+ * Name: ramtron_write
+ ****************************************************************************/
+
+#ifdef CONFIG_MTD_BYTE_WRITE
+static ssize_t ramtron_write(FAR struct mtd_dev_s *dev, off_t offset,
+                             size_t nbytes, FAR const uint8_t *buffer)
+{
+  FAR struct ramtron_dev_s *priv = (FAR struct ramtron_dev_s *)dev;
+  size_t remaining = nbytes;
+  size_t count;
+#ifdef CONFIG_RAMTRON_CHUNKING
+  size_t available;
+#endif
+
+  /* Reject requests that could wrap around the physical device. */
+
+  if (offset < 0 || offset > priv->part->size ||
+      nbytes > priv->part->size - (uint32_t)offset)
+    {
+      return -EINVAL;
+    }
+
+  if (nbytes == 0)
+    {
+      return 0;
+    }
+
+  DEBUGASSERT(buffer != NULL);
+  ramtron_lock(priv);
+
+  while (remaining > 0)
+    {
+      count = remaining;
+#ifdef CONFIG_RAMTRON_CHUNKING
+      if (priv->part->chunked)
+        {
+          /* Do not cross a write-buffer boundary on chunk-limited parts. */
+
+          available = priv->part->chunksize -
+                      offset % priv->part->chunksize;
+          if (count > available)
+            {
+              count = available;
+            }
+        }
+#endif
+
+      ramtron_writeenable(priv);
+      SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->devid), true);
+      SPI_SEND(priv->dev, RAMTRON_WRITE);
+      ramtron_sendaddr(priv, offset);
+      SPI_SNDBLOCK(priv->dev, buffer, count);
+      SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->devid), false);
+
+      offset    += count;
+      buffer    += count;
+      remaining -= count;
+    }
+
+  ramtron_unlock(priv->dev);
+  return nbytes;
+}
+#endif
+
 /****************************************************************************
  * Name: ramtron_ioctl
  ****************************************************************************/
@@ -863,6 +932,7 @@ static int ramtron_ioctl(FAR struct mtd_dev_s *dev,
         {
           FAR struct mtd_geometry_s *geo =
                     (FAR struct mtd_geometry_s *)((uintptr_t)arg);
+
           if (geo)
             {
               memset(geo, 0, sizeof(*geo));
@@ -892,6 +962,7 @@ static int ramtron_ioctl(FAR struct mtd_dev_s *dev,
         {
           FAR struct partition_info_s *info =
             (FAR struct partition_info_s *)arg;
+
           if (info != NULL)
             {
               info->numsectors  = priv->nsectors *
@@ -975,6 +1046,9 @@ FAR struct mtd_dev_s *ramtron_initialize(FAR struct spi_dev_s *dev,
       priv->mtd.bread  = ramtron_bread;
       priv->mtd.bwrite = ramtron_bwrite;
       priv->mtd.read   = ramtron_read;
+#ifdef CONFIG_MTD_BYTE_WRITE
+      priv->mtd.write  = ramtron_write;
+#endif
       priv->mtd.ioctl  = ramtron_ioctl;
       priv->mtd.name   = "ramtron";
       priv->dev        = dev;