diff --git a/src/hardware/fx2lafw/api.c b/src/hardware/fx2lafw/api.c
index 796749a3..213be9cf 100644
--- a/src/hardware/fx2lafw/api.c
+++ b/src/hardware/fx2lafw/api.c
@@ -87,6 +87,7 @@ static const uint32_t devopts[] = {
 	SR_CONF_CONN | SR_CONF_GET,
 	SR_CONF_SAMPLERATE | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
 	SR_CONF_TRIGGER_MATCH | SR_CONF_LIST,
+	SR_CONF_CAPTURE_RATIO | SR_CONF_GET | SR_CONF_SET,
 };
 
 static const char *channel_names[] = {
@@ -435,6 +436,9 @@ static int config_get(uint32_t key, GVariant **data, const struct sr_dev_inst *s
 	case SR_CONF_SAMPLERATE:
 		*data = g_variant_new_uint64(devc->cur_samplerate);
 		break;
+	case SR_CONF_CAPTURE_RATIO:
+		*data = g_variant_new_uint64(devc->capture_ratio);
+		break;
 	default:
 		return SR_ERR_NA;
 	}
@@ -477,6 +481,14 @@ static int config_set(uint32_t key, GVariant *data, const struct sr_dev_inst *sd
 		case SR_CONF_LIMIT_SAMPLES:
 			devc->limit_samples = g_variant_get_uint64(data);
 			break;
+		case SR_CONF_CAPTURE_RATIO:
+			devc->capture_ratio = g_variant_get_uint64(data);
+			if (devc->capture_ratio > 100) {
+				devc->capture_ratio = 0;
+				ret = SR_ERR;
+			} else
+				ret = SR_OK;
+			break;
 		default:
 			ret = SR_ERR_NA;
 	}
@@ -567,7 +579,12 @@ static int dev_acquisition_start(const struct sr_dev_inst *sdi, void *cb_data)
 	devc->empty_transfer_count = 0;
 
 	if ((trigger = sr_session_trigger_get(sdi->session))) {
-		devc->stl = soft_trigger_logic_new(sdi, trigger, 0);
+		int pre_trigger_samples = 0;
+		if (devc->limit_samples > 0)
+			pre_trigger_samples = devc->capture_ratio * devc->limit_samples/100;
+		devc->stl = soft_trigger_logic_new(sdi, trigger, pre_trigger_samples);
+		if (devc->stl == NULL)
+			return SR_ERR_MALLOC;
 		devc->trigger_fired = FALSE;
 	} else
 		devc->trigger_fired = TRUE;
diff --git a/src/hardware/fx2lafw/protocol.c b/src/hardware/fx2lafw/protocol.c
index d1d2d6a6..bc3228f1 100644
--- a/src/hardware/fx2lafw/protocol.c
+++ b/src/hardware/fx2lafw/protocol.c
@@ -304,6 +304,7 @@ SR_PRIV struct dev_context *fx2lafw_dev_new(void)
 	devc->fw_updated = 0;
 	devc->cur_samplerate = 0;
 	devc->limit_samples = 0;
+	devc->capture_ratio = 0;
 	devc->sample_wide = FALSE;
 	devc->stl = NULL;
 
@@ -391,6 +392,7 @@ SR_PRIV void fx2lafw_receive_transfer(struct libusb_transfer *transfer)
 	struct sr_datafeed_logic logic;
 	unsigned int num_samples;
 	int trigger_offset, cur_sample_count, unitsize;
+	int pre_trigger_samples;
 
 	sdi = transfer->user_data;
 	devc = sdi->priv;
@@ -458,8 +460,9 @@ SR_PRIV void fx2lafw_receive_transfer(struct libusb_transfer *transfer)
 		}
 	} else {
 		trigger_offset = soft_trigger_logic_check(devc->stl,
-				transfer->buffer, transfer->actual_length, NULL);
+			transfer->buffer, transfer->actual_length, &pre_trigger_samples);
 		if (trigger_offset > -1) {
+			devc->sent_samples += pre_trigger_samples;
 			packet.type = SR_DF_LOGIC;
 			packet.payload = &logic;
 			num_samples = cur_sample_count - trigger_offset;
diff --git a/src/hardware/fx2lafw/protocol.h b/src/hardware/fx2lafw/protocol.h
index fef0dd76..48be9930 100644
--- a/src/hardware/fx2lafw/protocol.h
+++ b/src/hardware/fx2lafw/protocol.h
@@ -80,6 +80,7 @@ struct dev_context {
 	/* Device/capture settings */
 	uint64_t cur_samplerate;
 	uint64_t limit_samples;
+	uint64_t capture_ratio;
 
 	/* Operational settings */
 	gboolean trigger_fired;