diff --git a/cyapa_fw_update.c b/cyapa_fw_update.c
index aca9bcf..4d1c5b5 100644
--- a/cyapa_fw_update.c
+++ b/cyapa_fw_update.c
@@ -112,6 +112,11 @@
 #define CYAPA_FW_TO_BIN(x)  ((x) - CYAPA_FW_OFFSET_START)
 #define CYAPA_BIN_TO_FW(x)  ((x) + CYAPA_FW_OFFSET_START)
 
+#define CYAPA_IDAC_0_START  0x7900
+#define CYAPA_IDAC_0_END    0x797F
+#define CYAPA_IDAC_0_SIZE   (CYAPA_IDAC_0_END - CYAPA_IDAC_0_START + 1)
+#define CYAPA_IDAC_0_DEF    0x08
+
 #define CYAPA_IDAC_1_START  0x7A00
 #define CYAPA_IDAC_1_END    0x7A7F
 #define CYAPA_IDAC_1_SIZE   (CYAPA_IDAC_1_END - CYAPA_IDAC_1_START + 1)
@@ -923,10 +928,14 @@
 void cyapa_fixup_fw_buffer(unsigned char* buf)
 {
 	/*
-	 * reset IDAC values blocks read from trackpad device,
-	 * because IDAC values are dynamic generated in running time,
-	 * and will be restored in flash, so we do not want this values.
+	 * Set IDAC regions in the image to a default pattern.
+	 * The values read from the device are dynamically generated at runtime
+	 * during calibration, and should be ignored. Setting these regions
+	 * to the pattern will ensure the resulting fw backup image has the
+	 * correct checksum.
 	 */
+	memset(&buf[CYAPA_FW_TO_BIN(CYAPA_IDAC_0_START)], CYAPA_IDAC_0_DEF,
+	       CYAPA_IDAC_0_SIZE);
 	memset(&buf[CYAPA_FW_TO_BIN(CYAPA_IDAC_1_START)], CYAPA_IDAC_1_DEF,
 	       CYAPA_IDAC_1_SIZE);
 	memset(&buf[CYAPA_FW_TO_BIN(CYAPA_IDAC_2_START)], CYAPA_IDAC_2_DEF,