diff --git a/driver-ztex.c b/driver-ztex.c
index de7011f3..41ee3b0c 100644
--- a/driver-ztex.c
+++ b/driver-ztex.c
@@ -223,6 +223,8 @@ static int64_t ztex_scanhash(struct thr_info *thr, struct work *work,
 
 	overflow = false;
 	int count = 0;
+	int validNonces = 0;
+	double errorCount = 0;
 
 	applog(LOG_DEBUG, "%s: entering poll loop", ztex->repr);
 	while (!(overflow || thr->work_restart)) {
@@ -274,10 +276,13 @@ static int64_t ztex_scanhash(struct thr_info *thr, struct work *work,
 
 				// do not count errors in the first 500ms after sendHashData (2x250 wait time)
 				if (count > 2) {
-					ztex->errorCount[ztex->freqM] += 1.0 / ztex->numNonces;
 					thr->cgpu->hw_errors++;
+					errorCount += (1.0 / ztex->numNonces);
 				}
 			}
+			else
+				validNonces++;
+
 
 			for (j=0; j<=ztex->extraSolutions; j++) {
 				nonce = hdata[i].goldenNonce[j];
@@ -313,6 +318,18 @@ static int64_t ztex_scanhash(struct thr_info *thr, struct work *work,
 		}
 	}
 
+	// only add the errorCount if we had at least some valid nonces or
+	// had no valid nonces in the last round
+	if (ztex->nonceCheckValid > 0 && validNonces == 0) {
+		applog(LOG_ERR, "%s: resetting %.1f errors", ztex->repr, errorCount);
+	}
+	else {
+		ztex->errorCount[ztex->freqM] += errorCount;
+	}
+
+	// remember the number of valid nonces for the check in the next round
+	ztex->nonceCheckValid = validNonces;
+
 	ztex->errorRate[ztex->freqM] = ztex->errorCount[ztex->freqM] /	ztex->errorWeight[ztex->freqM] * (ztex->errorWeight[ztex->freqM] < 100? ztex->errorWeight[ztex->freqM] * 0.01: 1.0);
 	if (ztex->errorRate[ztex->freqM] > ztex->maxErrorRate[ztex->freqM])
 		ztex->maxErrorRate[ztex->freqM] = ztex->errorRate[ztex->freqM];
diff --git a/libztex.c b/libztex.c
index d33c5c59..b3dfbebe 100644
--- a/libztex.c
+++ b/libztex.c
@@ -701,6 +701,9 @@ int libztex_prepare_device(struct libusb_device *dev, struct libztex_device** zt
 		newdev->maxErrorRate[cnt] = 0;
 	}
 
+	// fake that the last round found something valid
+	newdev->nonceCheckValid = 1;
+
 	newdev->usbbus = libusb_get_bus_number(dev);
 	newdev->usbaddress = libusb_get_device_address(dev);
 	sprintf(newdev->repr, "ZTEX %s-1", newdev->snString);
diff --git a/libztex.h b/libztex.h
index ffd056ea..c1d09b60 100644
--- a/libztex.h
+++ b/libztex.h
@@ -73,6 +73,8 @@ struct libztex_device {
 	double errorRate[256];
 	double maxErrorRate[256];
 
+	int16_t nonceCheckValid;
+
 	int16_t numberOfFpgas;
 	int selectedFpga;
 	bool parallelConfigSupport;