diff --git a/src/dispatch.c b/src/dispatch.c
index 1cc8e6a..601ee78 100644
--- a/src/dispatch.c
+++ b/src/dispatch.c
@@ -519,27 +519,24 @@ int raw1394_update_config_rom(raw1394handle_t handle, const quadlet_t
 			new_rom, size, rom_version);
 }
 
-int raw1394_add_config_rom_descriptor(raw1394handle_t handle,
-		const quadlet_t	immediate_key,
-		const quadlet_t	key,
-		const quadlet_t *new_rom_directory,
-		size_t size,
-		__u32 *out_token)
+int raw1394_add_config_rom_descriptor(raw1394handle_t handle, u_int32_t *token,
+		quadlet_t immediate_key, quadlet_t key,
+		const quadlet_t *data, size_t size)
 {
 	if (!handle) {
 		errno = EINVAL;
 		return -1;
 	}
 	if (handle->is_fw)
-		return fw_add_config_rom_descriptor(handle->mode.fw,
-			immediate_key, key, new_rom_directory, size, out_token);
+		return fw_add_config_rom_descriptor(handle->mode.fw, token,
+			immediate_key, key, data, size);
 	else {
-		errno = EINVAL;
+		errno = ENOSYS;
 		return -1;
 	}
 }
 
-int raw1394_remove_config_rom_descriptor(raw1394handle_t handle, __u32 token)
+int raw1394_remove_config_rom_descriptor(raw1394handle_t handle, u_int32_t token)
 {
 	if (!handle) {
 		errno = EINVAL;
@@ -548,7 +545,7 @@ int raw1394_remove_config_rom_descriptor(raw1394handle_t handle, __u32 token)
 	if (handle->is_fw)
 		return fw_remove_config_rom_descriptor(handle->mode.fw, token);
 	else {
-		errno = EINVAL;
+		errno = ENOSYS;
 		return -1;
 	}
 }
diff --git a/src/fw.c b/src/fw.c
index da275c5..877a6ad 100644
--- a/src/fw.c
+++ b/src/fw.c
@@ -1543,35 +1543,34 @@ fw_update_config_rom(fw_handle_t handle, const quadlet_t *new_rom,
 }
 
 int
-fw_add_config_rom_descriptor(fw_handle_t handle,
-	const quadlet_t	immediate_key,
-	const quadlet_t	key,
-	const quadlet_t *new_rom_directory,
-	size_t size,
-	__u32 *out_token)
+fw_add_config_rom_descriptor(fw_handle_t handle, u_int32_t *token,
+		quadlet_t immediate_key, quadlet_t key,
+		const quadlet_t *data, size_t size)
 {
 	struct fw_cdev_add_descriptor request;
-	int retval;
+	int err;
 
 	request.immediate	= immediate_key;
 	request.key		= key;
-	request.data		= ptr_to_u64(new_rom_directory);
-	request.length		= size;
+	request.data		= ptr_to_u64(data);
+	request.length		= size / 4;
 	request.handle		= 0;
 
-	retval = ioctl(handle->local_device->fd, FW_CDEV_IOC_ADD_DESCRIPTOR,
-		       &request);
-	if (retval < 0)
-		return -1;
+	err = ioctl(handle->local_device->fd, FW_CDEV_IOC_ADD_DESCRIPTOR,
+		    &request);
+	if (err)
+		return err;
+
+	if (token)
+		*token = request.handle;
 
-	*out_token = request.handle;
 	return 0;
 }
 
 int
-fw_remove_config_rom_descriptor(fw_handle_t handle, __u32 token)
+fw_remove_config_rom_descriptor(fw_handle_t handle, u_int32_t token)
 {
-	struct fw_cdev_remove_descriptor request = {token};
+	struct fw_cdev_remove_descriptor request = {.handle = token};
 
 	return ioctl(handle->local_device->fd, FW_CDEV_IOC_REMOVE_DESCRIPTOR,
 		     &request);
diff --git a/src/fw.h b/src/fw.h
index e64b2f3..cb1df01 100644
--- a/src/fw.h
+++ b/src/fw.h
@@ -202,13 +202,10 @@ int fw_start_fcp_listen(fw_handle_t handle);
 int fw_stop_fcp_listen(fw_handle_t handle);
 int fw_update_config_rom(fw_handle_t handle, const quadlet_t *new_rom,
 		   size_t size, unsigned char rom_version);
-int fw_add_config_rom_descriptor(fw_handle_t handle,
-	const quadlet_t	immediate_key,
-	const quadlet_t	key,
-	const quadlet_t *new_rom_directory,
-	size_t size,
-	__u32 *out_token);
-int fw_remove_config_rom_descriptor(fw_handle_t handle, __u32 token);
+int fw_add_config_rom_descriptor(fw_handle_t handle, u_int32_t *token,
+		   quadlet_t immediate_key, quadlet_t key,
+		   const quadlet_t *data, size_t size);
+int fw_remove_config_rom_descriptor(fw_handle_t handle, u_int32_t token);
 int fw_get_config_rom(fw_handle_t handle, quadlet_t *buffer,
 		   size_t buffersize, size_t *rom_size,
 		   unsigned char *rom_version);
diff --git a/src/raw1394.h b/src/raw1394.h
index 7239de3..312c3b3 100644
--- a/src/raw1394.h
+++ b/src/raw1394.h
@@ -1160,18 +1160,69 @@ const char *raw1394_get_libversion(void);
  * Returns: -1 (failure) if the version is incorrect, 
  * -2 (failure) if the new rom version is too big, or
  * 0 for success
+ *
+ * This function always fails on current kernels.
  **/
 
 int raw1394_update_config_rom(raw1394handle_t handle, const quadlet_t
         *new_rom, size_t size, unsigned char rom_version);
 
-int raw1394_add_config_rom_descriptor(raw1394handle_t handle,
-	const quadlet_t	immediate_key,
-	const quadlet_t	key,
-	const quadlet_t *new_rom_directory,
-	size_t size,
-	u_int32_t *out_token);
+/**
+ * raw1394_add_config_rom_descriptor - add contents to local Configuration ROM
+ * @handle: libraw1394 handle
+ * @token: handle of the Configuration ROM contents, written by libraw1394
+ * @immediate_key: if non-zero, immediate key to insert before pointer
+ * @key: upper 8 bits of root directory pointer
+ * @data: pointer to contents of descriptor block
+ * @size: size of descriptor block data, in bytes
+ *
+ * Add a directory, descriptor, or leaf block and optionally a preceding
+ * immediate key to the local node's Configuration ROM.  If successful, the
+ * kernel adds the descriptor and generates a bus reset to signal the change of
+ * the Configuration ROM to other nodes.  Note, on a system with multiple cards
+ * (multiple libraw1394 ports), the Configuration ROM of all local nodes is
+ * changed, not just the one which corresponds to the @handle.
+ *
+ * The changes to the Configuration ROM will be reverted when the client exits,
+ * or by raw1394_destroy_handle(), or by raw1394_remove_config_rom_descriptor().
+ * In order to be able to call the latter, the client needs to provide @token as
+ * pointer to an u_int32_t variable; otherwise @token may be NULL.
+ *
+ * @key specifies the upper 8 bits of the descriptor root directory pointer and
+ * @data and @size specify the contents.  The @key should be of the form
+ * 0xXX000000.  The offset part of the root directory entry will be filled in by
+ * the kernel.
+ *
+ * If not 0, @immediate_key specifies an immediate key which will be inserted
+ * before the root directory pointer.
+ *
+ * A directory can be added together with further subdirectories or descriptors
+ * or other leaves; just provide all data concatenated in @data and set the
+ * respective offsets in your directory entries.
+ *
+ * The CRC in the first quadlet of any directory, subdirectory, leaf or
+ * descriptor may be left blank.  The kernel will compute and fill in these
+ * CRCs.
+ *
+ * @immediate_key, @key, and @data array elements are host-endian quadlets.
+ *
+ * Returns: 0 on success or -1 on failure (sets errno)
+ *
+ * History: New function in libraw1394 v2.1.0.
+ **/
+int raw1394_add_config_rom_descriptor(raw1394handle_t handle, u_int32_t *token,
+	quadlet_t immediate_key, quadlet_t key,
+	const quadlet_t *data, size_t size);
 
+/**
+ * raw1394_remove_config_rom_descriptor - remove contents from Configuration ROM
+ * @handle: libraw1394 handle
+ * @token: handle of the Configuration ROM contents
+ *
+ * Returns: 0 on success or -1 on failure (sets errno)
+ *
+ * History: New function in libraw1394 v2.1.0.
+ **/
 int raw1394_remove_config_rom_descriptor(raw1394handle_t handle,
 	u_int32_t token);
 
diff --git a/tools/testlibraw.c b/tools/testlibraw.c
index 6547c00..8fe8b26 100644
--- a/tools/testlibraw.c
+++ b/tools/testlibraw.c
@@ -15,6 +15,7 @@
 #include <sys/poll.h>
 #include <stdlib.h>
 #include <time.h>
+#include <unistd.h>
 #include <arpa/inet.h>
 
 #include "../src/raw1394.h"
@@ -117,10 +118,36 @@ read_topology_map(raw1394handle_t handle)
 		printf("    0x%08x\n", ntohl(map[3 + i]));
 }
 
+static const quadlet_t unit_directory_data[] = {
+	0x00060000,	/* directory_length (CRC left blank)	*/
+	0x1258595a,	/* a bogus unit_specifier_id: XYZ	*/
+	0x13616263,	/* unit_sw_version: abc			*/
+	0x036c7277,	/* a bogus vendor OUI: lrw		*/
+	0x81000003,	/* textual descriptor offset		*/
+	0x17000001,	/* model: 1				*/
+	0x81000007,	/* textual descriptor offset		*/
+
+	0x00050000,	/* descriptor_length (CRC left blank)	*/
+	0x00000000,	/* descriptor_type: text		*/
+	0x00000000,	/* minimal ASCII, English		*/
+	0x6c696272,	/* "libr"				*/
+	0x61773133,	/* "aw13"				*/
+	0x39340000,	/* "94"					*/
+
+	0x00050000,	/* descriptor_length (CRC left blank)	*/
+	0x00000000,	/* descriptor_type: text		*/
+	0x00000000,	/* minimal ASCII, English		*/
+	0x74657374,	/* "test"				*/
+	0x6c696272,	/* "libr"				*/
+	0x61770000,	/* "aw"					*/
+};
+#define IEEE1212_KEY_UNIT_DIRECTORY 0xd1000000
+
 static void
 test_config_rom(raw1394handle_t handle)
 {
 	quadlet_t rom[0x100] = { 0, };
+	u_int32_t token;
 	size_t rom_size;
 	unsigned char rom_version;
 	int i, retval;
@@ -135,7 +162,23 @@ test_config_rom(raw1394handle_t handle)
 		printf("    0x%08x\n", rom[i]);
 
 	retval = raw1394_update_config_rom(handle, rom, rom_size, rom_version);
-	printf("    update_config_rom returned %d\n", retval);
+	perror("    raw1394_update_config_rom failed with error");
+
+	retval = raw1394_add_config_rom_descriptor(handle, &token,
+			0, IEEE1212_KEY_UNIT_DIRECTORY,
+			unit_directory_data, sizeof(unit_directory_data));
+	if (retval) {
+		printf("    raw1394_add_config_rom_descriptor failed with error");
+		return;
+	}
+
+	printf("    added unit '0x58595a:0x616263', reverting in 5 seconds\n");
+	sleep(5);
+	retval = raw1394_remove_config_rom_descriptor(handle, token);
+	if (retval)
+		printf("    raw1394_remove_config_rom_descriptor failed with error");
+	else
+		printf("    unit '0x58595a:0x616263' removed\n");
 }
 
 static void