diff --git a/edid-decode.c b/edid-decode.c
index 2f2f1c5..29f8f88 100644
--- a/edid-decode.c
+++ b/edid-decode.c
@@ -55,6 +55,7 @@ static int did_detailed_timing = 0;
 static int has_name_descriptor = 0;
 static int has_serial_string = 0;
 static int has_ascii_string = 0;
+static int has_GP_ascii_string = 0;
 static int has_range_descriptor = 0;
 static int has_preferred_timing = 0;
 static int has_valid_checksum = 1;
@@ -64,6 +65,7 @@ static int has_valid_cvt = 1;
 static int has_valid_serial_number = 0;
 static int has_valid_serial_string = 0;
 static int has_valid_ascii_string = 0;
+static int has_valid_GP_ascii_string = 0;
 static int has_valid_name_descriptor = 0;
 static int has_valid_detailed_blocks = 0;
 static int has_valid_descriptor_ordering = 1;
@@ -2528,6 +2530,53 @@ static int parse_cta(const unsigned char *x)
 	return ret;
 }
 
+
+static const char *feature_support_flags[] = {
+	"De-interlacing",
+	"Support ACP, ISRC1, or ISRC2packets",
+	"Fixed pixel format",
+	"Fixed timing",
+	"Power management (DPM)",
+	"Audio input override",
+	"Separate audio inputs provided",
+	"Audio support on video interface"
+};
+
+static void print_flag_lines(const char *indent, const char *label, unsigned char flag_byte, const char **flags) {
+	if (flag_byte) {
+		printf("%s\n", label);
+		for (int i = 0; i < 8; i++) {
+			if (flag_byte & (1<<i)) {
+				printf("%s%s\n", indent, flags[i]);
+			}
+		}
+	}
+}
+
+static void parse_displayid_parameters(const unsigned char *x) {
+	int revisionflags=x[1];
+	int len=x[2];
+	if (revisionflags) {
+		printf("  Unexpected revision and flags (0x%02x != 0)\n", revisionflags);
+	}
+	if (len != 12) {
+		printf("  Length is different than expected (%d != 12)\n", len);
+		printf("  ");
+		hex_block(x + 3, len);
+	} else {
+		printf("  Image size: %.1f mm x %.1f mm\n", ((x[4]<<8) + x[3]) / 10.0, ((x[6]<<8) + x[5]) / 10.0);
+		printf("  Pixels: %d x %d\n", (x[8]<<8) + x[7], (x[10]<<8) + x[9]);
+		print_flag_lines("    ", "  Feature support flags:", x[11], feature_support_flags);
+
+		if (x[12] != 0xff) {
+			printf("  Gamma: %.2f\n", ((x[12] + 100.0) / 100.0));
+		}
+		printf("  Aspect ratio: %.2f\n", ((x[13] + 100.0) / 100.0));
+		printf("  Dynamic bpc native: %d\n", (x[14] & 0xf) + 1);
+		printf("  Dynamic bpc overall: %d\n", ((x[14] >> 4) & 0xf) + 1);
+	} // else
+}
+
 static void parse_displayid_detailed_timing(const unsigned char *x)
 {
 	unsigned ha, hbl, hso, hspw;
@@ -2713,18 +2762,343 @@ static const struct {
 	{2560, 1600, 120, 16, 10, 203217, 552750, 1},
 };
 
+const char *displayid_vesa_dmt_timings[] = {
+	"640x350@85Hz",
+	"640x400@85Hz",
+	"720x400@85Hz",
+	"640x480@60Hz",
+	"640x480@72Hz",
+	"640x480@75Hz",
+	"640x480@85Hz",
+	"800x600@56Hz",
+	"800x600@60Hz",
+	"800x600@72Hz",
+	"800x600@75Hz",
+	"800x600@85Hz",
+	"800x600@120Hz (RB)",
+	"848x480@60Hz",
+	"1024x768@43Hz (INT)",
+	"1024x768@60Hz",
+	"1024x768@70Hz",
+	"1024x768@75Hz",
+	"1024x768@85Hz",
+	"1024x768@120Hz (RB)",
+	"1152x864@75Hz",
+	"1280x768@60Hz (RB)",
+	"1280x768@60Hz",
+	"1280x768@75Hz",
+	"1280x768@85Hz",
+	"1280x768@120Hz (RB)",
+	"1280x800@60Hz (RB)",
+	"1280x800@60Hz",
+	"1280x800@75Hz",
+	"1280x800@85Hz",
+	"1280x800@120Hz (RB)",
+	"1280x960@60Hz",
+	"1280x960@85Hz",
+	"1280x960@120Hz (RB)",
+	"1280x1024@60Hz",
+	"1280x1024@75Hz",
+	"1280x1024@85Hz",
+	"1280x1024@120Hz (RB)",
+	"1360x768@60Hz",
+	"1360x768@120Hz (RB)",
+	"1400x1050@60Hz (RB)",
+	"1400x1050@60Hz",
+	"1400x1050@75Hz",
+	"1400x1050@85Hz",
+	"1400x1050@120Hz (RB)",
+	"1440x900@60Hz (RB)",
+	"1440x900@60Hz",
+	"1440x900@75Hz",
+	"1440x900@85Hz",
+	"1440x900@120Hz (RB)",
+	"1600x1200@60Hz",
+	"1600x1200@65Hz",
+	"1600x1200@70Hz",
+	"1600x1200@75Hz",
+	"1600x1200@85Hz",
+	"1600x1200@120Hz (RB)",
+	"1680x1050@60Hz (RB)",
+	"1680x1050@60Hz",
+	"1680x1050@75Hz",
+	"1680x1050@85Hz",
+	"1680x1050@120Hz (RB)",
+	"1792x1344@60Hz",
+	"1792x1344@75Hz",
+	"1792x1344@120Hz (RB)",
+	"1856x1392@60Hz",
+	"1856x1392@75Hz",
+	"1856x1392@120Hz (RB)",
+	"1920x1200@60Hz (RB)",
+	"1920x1200@60Hz",
+	"1920x1200@75Hz",
+	"1920x1200@85Hz",
+	"1920x1200@120Hz (RB)",
+	"1920x1440@60Hz",
+	"1920x1440@75Hz",
+	"1920x1440@120Hz (RB)",
+	"2560x1600@60Hz (RB)",
+	"2560x1600@60Hz",
+	"2560x1600@75Hz",
+	"2560x1600@85Hz",
+	"2560x1600@120Hz (RB)",
+};
+
+const char *displayid_cta_timings[] = {
+	"640x480p@59.94/60Hz 4:3",
+	"720x480p@59.94/60Hz 4:3",
+	"720x480p@59.94/60Hz 16:9",
+	"1280x720p@59.94/60Hz 16:9",
+	"1920x1080i@59.94/60Hz 16:9",
+	"720(1440)x480i@59.94/60Hz 4:3",
+	"720(1440)x480i@59.94/60Hz 16:9",
+	"720(1440)x240p@59.94/60Hz 4:3",
+	"720(1440)x240p@59.94/60Hz 16:9",
+	"2880x480i@59.94/60Hz 4:3",
+	"2880x480i@59.94/60Hz 16:9",
+	"2880x240p@59.94/60Hz 4:3",
+	"2880x240p@59.94/60Hz 16:9",
+	"1440x480p@59.94/60Hz 4:3",
+	"1440x480p@59.94/60Hz 16:9",
+	"1920x1080p@59.94/60Hz 16:9",
+	"720x576p@50Hz 4:3",
+	"720x576p@50Hz 16:9",
+	"1280x720p@50Hz 16:9",
+	"1920x1080i@50Hz 16:9",
+	"720(1440)x576i@50Hz 4:3",
+	"720(1440)x576i@50Hz 16:9",
+	"720(1440)x288p@50Hz 4:3",
+	"720(1440)x288p@50Hz 16:9",
+	"2880x576i@50Hz 4:3",
+	"2880x576i@50Hz 16:9",
+	"2880x288p@50Hz 4:3",
+	"2880x288p@50Hz 16:9",
+	"1440x576p@50Hz 4:3",
+	"1440x576p@50Hz 16:9",
+	"1920x1080p@50Hz 16:9",
+	"1920x1080p@23.97/24Hz 16:9",
+	"1920x1080p@25Hz 16:9",
+	"1920x1080p@29.97/30Hz 16:9",
+	"2880x480p@59.94/60Hz 4:3",
+	"2880x480p@59.94/60Hz 16:9",
+	"2880x576p@50Hz 4:3",
+	"2880x576p@50Hz 16:9",
+	"1920x1080i@50Hz 16:9",
+	"1920x1080i@100Hz 16:9",
+	"1280x720p@100Hz 16:9",
+	"720x576p@100Hz 4:3",
+	"720x576p@100Hz 16:9",
+	"720(1440)x576i@100Hz 4:3",
+	"720(1440)x576i@100Hz 16:9",
+	"1920x1080i@119.88/120Hz 16:9",
+	"1280x720p@119.88/120Hz 16:9",
+	"720x480p@119.88/120Hz 4:3",
+	"720x480p@119.88/120Hz 16:9",
+	"720(1440)x480i@119.88/120Hz 4:3",
+	"720(1440)x480i@119.88/120Hz 16:9",
+	"720x576p@200Hz 4:3",
+	"720x576p@200Hz 16:9",
+	"720(1440)x576i@200Hz 4:3",
+	"720(1440)x576i@200Hz 16:9",
+	"720x480p@239.76/240Hz 4:3",
+	"720x480p@239.76/240Hz 16:9",
+	"720(1440)x480i@239.76/240Hz 4:3",
+	"720(1440)x480i@239.76/240Hz 16:9",
+	"1280x720p@23.97/24Hz 16:9",
+	"1280x720p@25Hz 16:9",
+	"1280x720p@29.97/30Hz 16:9",
+	"1920x1080p@120Hz 16:9",
+	"1920x1080p@100Hz 16:9",
+};
+
+static void parse_displayid_timing(const unsigned char *x, int expectedlen, const char** list)
+{
+	int revisionflags=x[1];
+	int len=x[2];
+	if (revisionflags) {
+		printf("  Unexpected revision and flags (0x%02x != 0)\n", revisionflags);
+	}
+	if (len > expectedlen) {
+		printf("  Length is greater than expected (%d > %d)\n", len, expectedlen);
+	} else if (len < expectedlen) {
+		printf("  Length is less than expected (%d < %d)\n", len, expectedlen);
+	}
+	x += 3;
+	for (int i = 0; i < len * 8; i++) {
+		if (x[i>>3] & (1<<(i&7))) {
+			if ((i>>3) < expectedlen) {
+				printf("  %s\n", list[i]);
+			} else {
+				printf("  #%d\n", i+1);
+			}
+		}
+	}
+}
+
+static void parse_displayid_gp_string(const unsigned char *x)
+{
+	int revisionflags=x[1];
+	if (revisionflags) {
+		printf("  Unexpected revision and flags (0x%02x != 0)\n", revisionflags);
+	}
+}
+
+static const char *bpc444[] = {"6", "8", "10", "12", "14", "16", NULL, NULL};
+static const char *bpc4xx[] = {"8", "10", "12", "14", "16", NULL, NULL, NULL};
+static const char *audiorates[] = {"32", "44.1", "48", NULL, NULL, NULL, NULL, NULL};
+
+static const char *colorspace_eotf_combinations[] = {
+	"sRGB",
+	"BT.601",
+	"BT.709/BT.1886",
+	"Adobe RGB",
+	"DCI-P3",
+	"BT.2020",
+	"BT.2020/SMPTE ST 2084"
+};
+
+static const char *colorspace_eotf_reserved[] = {NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL};
+
+static const char *colorspaces[] = {
+	"Undefined",
+	"sRGB",
+	"BT.601",
+	"BT.709",
+	"Adobe RGB",
+	"DCI-P3",
+	"BT.2020",
+	"Custom"
+};
+
+static const char *eotfs[] = {
+	"Undefined",
+	"sRGB",
+	"BT.601",
+	"BT.1886",
+	"Adobe RGB",
+	"DCI-P3",
+	"BT.2020",
+	"Gamma function",
+	"SMPTE ST 2084",
+	"Hybrid Log",
+	"Custom"
+};
+
+static void print_flags(const char *label, unsigned char flag_byte, const char **flags, int reverse)
+{
+	if (flag_byte) {
+		printf("%s: ", label);
+		int countflags = 0;
+		for (int i = 0; i < 8; i++) {
+			if (flag_byte & (1<<(reverse?7-i:i))) {
+				if (countflags)
+					printf(", ");
+				if (flags[i])
+					printf("%s", flags[i]);
+				else
+					printf("Undefined(%d)", i);
+				countflags++;
+			}
+		}
+		printf("\n");
+	}
+}
+
+static void parse_displayid_interface_features(const unsigned char *x)
+{
+	int revisionflags=x[1];
+	int len=x[2];
+	if (revisionflags) {
+		printf("  Unexpected revision and flags (0x%02x != 0)\n", revisionflags);
+	}
+	if (len < 9) {
+		printf("  Length is less than expected (%d < 9)\n", len);
+		printf("  ");
+		hex_block(x + 3, len);
+	} else {
+		print_flags("  Supported bpc for RGB encoding", x[3], bpc444, 0);
+		print_flags("  Supported bpc for YCbCr 4:4:4 encoding", x[4], bpc444, 0);
+		print_flags("  Supported bpc for YCbCr 4:2:2 encoding", x[5], bpc4xx, 0);
+		print_flags("  Supported bpc for YCbCr 4:2:0 encoding", x[6], bpc4xx, 0);
+		if (x[7])
+			printf("  Minimum pixel rate at which YCbCr 4:2:0 encoding is supported: %.3f MHz\n", 74.25 * x[7]);
+		print_flags("  Supported audio capability and features (kHz)", x[8], audiorates, 1);
+		print_flags("  Supported color space and EOTF standard combination 1", x[9], colorspace_eotf_combinations, 0);
+		print_flags("  Supported color space and EOTF standard combination 2", x[10], colorspace_eotf_reserved, 0);
+		int i = 0;
+		if (len >= 9 && x[11] > 0) {
+			printf("  Supported color space and EOTF additional combinations:");
+			for (i = 1; i <= x[11]; i++) {
+				if (i > 7) {
+					printf("\n  Number of additional color space and EOTF combinations (%d) is greater than allowed (7).", x[11]);
+					break;
+				} else if (9 + i > len) {
+					printf("\n  Number of additional color space and EOTF combinations (%d) is too many to fit in block (%d).", x[11], len - 9);
+					break;
+				}
+
+				const char *colorspace = "Out of range";
+				const char *eotf = "Out of range";
+				int colorspace_index = (x[11 + i] >> 4) & 0xf;
+				int eotf_index = x[11 + i] & 0xf;
+				if (colorspace_index < sizeof(colorspaces) / sizeof(colorspaces[0])) {
+					colorspace = colorspaces[colorspace_index];
+				}
+				if (eotf_index < sizeof(eotfs) / sizeof(eotfs[0])) {
+					eotf = eotfs[eotf_index];
+				}
+
+				if (i > 1)
+					printf(", ");
+				if (!strcmp(colorspace, eotf)) {
+					printf("%s", colorspace);
+				} else {
+					printf("%s/%s", colorspace, eotf);
+				}
+			} // for
+			printf("\n");
+		} // x[11]
+		if (len > 9 + i) {
+			printf("  Length is greater than expected (%d > %d)\n", len, 9 + i);
+			printf("  ");
+			hex_block(x + 11 + i, len - 9 - i);
+		} else if (len != 9 + i)  {
+			printf("  Length is unexpected (%d != %d)\n", len, 9 + i);
+		}
+	}
+}
+
+static void parse_displayid_ContainerID(const unsigned char *x)
+{
+	int revisionflags=x[1];
+	int len=x[2];
+	if (revisionflags) {
+		printf("  Unexpected revision and flags (0x%02x != 0)\n", revisionflags);
+	}
+	x += 3;
+	if (len != 16) {
+		printf("  Length is unexpected (%d != 16)\n", len);
+		printf("  ");
+		hex_block(x, len);
+	} else {
+		printf("  %02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x\n",x[0],x[1],x[2],x[3],x[4],x[5],x[6],x[7],x[8],x[9],x[10],x[11],x[12],x[13],x[14],x[15]);
+	}
+}
+
 static int parse_displayid(const unsigned char *x)
 {
 	const unsigned char *orig = x;
 	unsigned version = x[1];
 	unsigned length = x[2];
+	unsigned producttype = x[3];
 	unsigned ext_count = x[4];
 	unsigned i;
 
 	cur_block = "DisplayID";
 
-	printf("Length %u, version %u.%u, extension count %u\n",
-	       length, version >> 4, version & 0xf, ext_count);
+	printf("Length %u, version %u.%u, type %u, extension count %u\n",
+	       length, version >> 4, version & 0xf, producttype, ext_count);
 
 	unsigned offset = 5;
 	while (length > 0) {
@@ -2734,33 +3108,49 @@ static int parse_displayid(const unsigned char *x)
 		if (len == 0)
 			break;
 		switch (tag) {
+		
+		// DisplayID 1.3:
 		case 0:
-			printf("Product ID Block\n");
+			printf("Product ID Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 1:
-			printf("Display Parameters Block\n");
+			printf("Display Parameters Block (%02Xh):\n", tag);
+			parse_displayid_parameters(x + offset);
 			break;
 		case 2:
-			printf("Color Characteristics Block\n");
+			printf("Color Characteristics Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 3: {
-			printf("Type 1 Detailed Timings Block\n");
+			printf("Type 1 Detailed Timings Block (%02Xh)\n", tag);
 			for (i = 0; i < len / 20; i++) {
 				parse_displayid_detailed_timing(&x[offset + 3 + (i * 20)]);
 			}
 			break;
 		}
 		case 4:
-			printf("Type 2 Detailed Timings Block\n");
+			printf("Type 2 Detailed Timings Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 5:
-			printf("Type 3 Short Timings Block\n");
+			printf("Type 3 Short Timings Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 6:
-			printf("Type 4 DMT Timings Block\n");
+			printf("Type 4 DMT Timings Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 7:
-			printf("Type 1 VESA DMT Timings Block\n");
+			printf("Type 1 VESA DMT Timings Block (%02Xh)\n", tag);
+			#if 0
+			parse_displayid_timing(x + offset, 10, displayid_vesa_dmt_timings);
+			#else
 			for (i = 0; i < min(len, 10) * 8; i++) {
 				if (x[offset + 3 + i / 8] & (1 << (i % 8))) {
 					printf("  %ux%u%s@%uHz %s%u:%u HorFreq: %.3f kHz Clock: %.3f MHz\n",
@@ -2779,33 +3169,51 @@ static int parse_displayid(const unsigned char *x)
 					max_pixclk_khz = max(max_pixclk_khz, displayid_vesa_dmt[i].pixclk_khz);
 				}
 			}
+			#endif
 			break;
 		case 8:
-			printf("CTA Timings Block\n");
+			printf("CTA Timings Block (%02Xh):\n", tag);
+			parse_displayid_timing(x + offset, 8, displayid_cta_timings);
 			break;
 		case 9:
-			printf("Video Timing Range Block\n");
+			printf("Video Timing Range Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 0xa:
-			printf("Product Serial Number Block\n");
+			printf("Product Serial Number Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 0xb:
-			printf("GP ASCII String Block\n");
+			printf("GP ASCII String Block (%02Xh): %s\n", tag, extract_string("GP ASCII String", x + offset + 3, &has_valid_GP_ascii_string, len));
+			has_GP_ascii_string = 1;
+			parse_displayid_gp_string(x + offset);
 			break;
 		case 0xc:
-			printf("Display Device Data Block\n");
+			printf("Display Device Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 0xd:
-			printf("Interface Power Sequencing Block\n");
+			printf("Interface Power Sequencing Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 0xe:
-			printf("Transfer Characteristics Block\n");
+			printf("Transfer Characteristics Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 0xf:
-			printf("Display Interface Block\n");
+			printf("Display Interface Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 0x10:
-			printf("Stereo Display Interface Block\n");
+			printf("Stereo Display Interface Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		case 0x12: {
 			unsigned capabilities = x[offset + 3];
@@ -2817,7 +3225,7 @@ static int parse_displayid(const unsigned char *x)
 			unsigned tile_height = x[offset + 9] | (x[offset + 10] << 8);
 			unsigned pix_mult = x[offset + 11];
 
-			printf("Tiled Display Topology Block\n");
+			printf("Tiled Display Topology Block (%02Xh)\n", tag);
 			printf("  Capabilities: 0x%08x\n", capabilities);
 			printf("  Num horizontal tiles: %u Num vertical tiles: %u\n", num_h_tile + 1, num_v_tile + 1);
 			printf("  Tile location: %u, %u\n", tile_h_location, tile_v_location);
@@ -2841,8 +3249,80 @@ static int parse_displayid(const unsigned char *x)
 			}
 			break;
 		}
+
+		// DisplayID 2.0
+		case 0x20:
+			printf("Product ID Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
+			break;
+		case 0x21:
+			printf("Display Parameters Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
+			break;
+		case 0x22:
+			printf("Type 7 Timing - Detailed Timing Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
+			break;
+		case 0x23:
+			printf("Type 8 Timing - Enumerated Timing Code Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
+			break;
+		case 0x24:
+			printf("Type 9 Timing - Formula-based Timing Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
+			break;
+		case 0x25:
+			printf("Dynamic Video Timing Range Limits Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
+			break;
+		case 0x26:
+			printf("Display Interface Features Data Block (%02Xh):\n", tag);
+			parse_displayid_interface_features(x + offset);
+			break;
+		case 0x27:
+			printf("Stereo Display Interface Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
+			break;
+		case 0x28:
+			printf("Tiled Display Topology Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
+			break;
+		case 0x29:
+			printf("ContainerID Data Block (%02Xh):\n", tag);
+			parse_displayid_ContainerID(x + offset);
+			break;
+
+		// 2Ah .. 7Dh RESERVED for Additional VESA-defined Data Blocks
+
+		case 0x7e: // DisplayID 2.0
+		case 0x7f: // DisplayID 1.3
+			printf("Vendor-specific Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
+			break;
+
+		// 7Fh .. 80h RESERVED
+
+		case 0x81:
+			printf("CTA DisplayID Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
+			break;
+
+		// 82h .. FFh RESERVED
+		
 		default:
-			printf("Unknown DisplayID Data Block 0x%x\n", tag);
+			printf("Unknown DisplayID Data Block (%02Xh)\n", tag);
+			printf("  ");
+			hex_block(x + offset + 3, len);
 			break;
 		}
 		length -= len + 3;
@@ -3687,6 +4167,7 @@ static int edid_from_file(const char *from_file, const char *to_file,
 	    !has_valid_range_descriptor ||
 	    (has_name_descriptor && !has_valid_name_descriptor) ||
 	    (has_serial_string && !has_valid_serial_string) ||
+		(has_GP_ascii_string && !has_valid_GP_ascii_string) ||
 	    (has_ascii_string && !has_valid_ascii_string)) {
 		conformant = 0;
 		printf("EDID block does not conform:\n");
@@ -3709,6 +4190,8 @@ static int edid_from_file(const char *from_file, const char *to_file,
 			printf("\tInvalid Monitor Name descriptor\n");
 		if (has_ascii_string && !has_valid_ascii_string)
 			printf("\tInvalid ASCII string\n");
+		if (has_GP_ascii_string && !has_valid_GP_ascii_string)
+			printf("\tInvalid GP ASCII string\n");
 		if (has_serial_string && !has_valid_serial_string)
 			printf("\tInvalid serial string\n");
 	}
