diff --git a/README.devices b/README.devices
index 3591fe9c..136db62c 100644
--- a/README.devices
+++ b/README.devices
@@ -10,7 +10,7 @@ Firmware
 --------
 
 Some devices supported by libsigrok need a firmware to be uploaded every time
-the device is connected to the PC (usually via USB), before it can be used. 
+the device is connected to the PC (usually via USB), before it can be used.
 
 The default location where libsigrok expects the firmware files is:
 
@@ -288,10 +288,16 @@ a short list for convenience:
    interface panel on top.
  - Digitek DT4000ZC: Briefly press the "RS232" button.
  - Gossen Metrawatt Metrahit 1x/2x devices, driver gmc-mh-1x-2x-rs232:
-   Power on the device with the "DATA" button pressed. Additionally Metrahit
-   2x devices must be configured for the respective interface type.
+   - Power on the device with the "DATA" button pressed.
+   - Metrahit 2x devices must be configured for the respective interface type.
  - Gossen Metrawatt Metrahit 2x devices, driver gmc-mh-2x-bd232:
-   The device must be configured for the respective interface type.
+   - 'BD232' interface:
+      The multimeter must be configured for the respective interface type.
+   - 'SI232-II' interface ("PC Mode"):
+      The multimeter must be configured for interface type 'BD232' (all),
+      'SI232 online' (28-29S) or 'SI232 store' (22-26x). The interface must
+      be configured to the same baud rate as the host (default 9600).
+      Multimeter and interface must be configured to the same address.
  - Norma DM950: If the interface doesn't work (e.g. USB-RS232 converter), power
    on the device with "FUNC" pressed (to power the interface from the DMM).
  - PCE PCE-DM32: Briefly press the "RS232" button.
diff --git a/hardware/gmc-mh-1x-2x/api.c b/hardware/gmc-mh-1x-2x/api.c
index 4084bf65..8c413e60 100644
--- a/hardware/gmc-mh-1x-2x/api.c
+++ b/hardware/gmc-mh-1x-2x/api.c
@@ -436,13 +436,13 @@ static int config_get(int key, GVariant **data, const struct sr_dev_inst *sdi,
 		      const struct sr_probe_group *probe_group)
 {
 	int ret;
+	struct dev_context *devc;
 
 	(void)sdi;
 	(void)data;
 	(void)probe_group;
 
 	ret = SR_OK;
-	struct dev_context *devc;
 
 	(void)probe_group;
 
@@ -621,7 +621,7 @@ SR_PRIV struct sr_dev_driver gmc_mh_1x_2x_rs232_driver_info = {
 
 SR_PRIV struct sr_dev_driver gmc_mh_2x_bd232_driver_info = {
 	.name = "gmc-mh-2x-bd232",
-	.longname = "Gossen Metrawatt Metrahit 2x, 'BD232' interface",
+	.longname = "Gossen Metrawatt Metrahit 2x, 'BD232'/'SI232-II' interface",
 	.api_version = 1,
 	.init = init_2x_bd232,
 	.cleanup = cleanup_2x_bd232,
diff --git a/hardware/gmc-mh-1x-2x/protocol.c b/hardware/gmc-mh-1x-2x/protocol.c
index b0163dbd..ceb138e9 100644
--- a/hardware/gmc-mh-1x-2x/protocol.c
+++ b/hardware/gmc-mh-1x-2x/protocol.c
@@ -1320,11 +1320,15 @@ int req_stat14(const struct sr_dev_inst *sdi, gboolean power_on)
 
 	if (power_on) {
 		sr_info("Write some data and wait 3s to turn on powered off device...");
-		if ((serial_write(serial, msg, sizeof(msg)) == -1) ||
-				(serial_write(serial, msg, sizeof(msg)) == -1) ||
-				(serial_write(serial, msg, sizeof(msg)) == -1))
+		if (serial_write(serial, msg, sizeof(msg)) < 0)
 			return SR_ERR;
-		g_usleep(3*1000*1000);
+		g_usleep(1*1000*1000);
+		if (serial_write(serial, msg, sizeof(msg)) < 0)
+			return SR_ERR;
+		g_usleep(1*1000*1000);
+		if (serial_write(serial, msg, sizeof(msg)) < 0)
+			return SR_ERR;
+		g_usleep(1*1000*1000);
 		serial_flush(serial);
 	}