diff --git a/Firmware/xyzcal.cpp b/Firmware/xyzcal.cpp
index 725150f31..cdf234b8d 100644
--- a/Firmware/xyzcal.cpp
+++ b/Firmware/xyzcal.cpp
@@ -369,7 +369,7 @@ void xyzcal_histo_pixels_32x32(uint8_t* pixels, uint16_t* histo)
 void xyzcal_adjust_pixels(uint8_t* pixels, uint16_t* histo)
 {
 	uint8_t l;
-	uint16_t max_c = histo[0];
+	uint16_t max_c = histo[1];
 	uint8_t max_l = 1;
 	for (l = 1; l < 16; l++)
 	{
@@ -381,10 +381,10 @@ void xyzcal_adjust_pixels(uint8_t* pixels, uint16_t* histo)
 		}
 	}
 	DBG(_n("max_c=%2d max_l=%d\n"), max_c, max_l);
-	for (l = 15; l > 8; l--)
+	for (l = 14; l > 8; l--)
 		if (histo[l] >= 10)
 			break;
-	uint8_t pix_min = (max_l + 1) << 4;
+	uint8_t pix_min = (max_l - 1) << 4;
 	uint8_t pix_max = l << 4;
 	uint8_t pix_dif = pix_max - pix_min;
 	DBG(_n(" min=%d max=%d dif=%d\n"), pix_min, pix_max, pix_dif);