diff --git a/fbird_batch.c b/fbird_batch.c
index 96eedb8f..ff7e220d 100644
--- a/fbird_batch.c
+++ b/fbird_batch.c
@@ -554,14 +554,10 @@ int fbird_batch_add_impl(fbird_batch *fb_batch, zval *args, int argc)
 				/* BLOB ID as hex string "HHHHHHHH:LLLLLLLL" (17 characters)
 				 * Format: 8 hex digits (high 32-bit), colon, 8 hex digits (low 32-bit)
 				 * jane: #516 - was 13 chars (4 hex low), now 17 chars (8 hex low, full 32-bit)
-				/* BLOB ID as hex string "HHHHHHHH:LLLLLLLL" (17 characters)
-				 * Format: 8 hex digits (high 32-bit), colon, 8 hex digits (low 32-bit)
-				 * jane: #516 - was 13 chars (4 hex low), now 17 chars (8 hex low, full 32-bit)
-				 * Example: "74292B00:7FFC"
-				 */
+				 * Example: "74292B00:00007FFC" */
 				convert_to_string(b_var);
 
-				if (Z_STRLEN_P(b_var) == BLOB_ID_LEN &&
+				if (((Z_STRLEN_P(b_var) == BLOB_ID_LEN || Z_STRLEN_P(b_var) == BLOB_ID_LEN_LEGACY)) &&
 					_php_fbird_string_to_quad(Z_STRVAL_P(b_var), (ISC_QUAD *)data_ptr)) {
 					/* Valid BLOB ID parsed and written to message buffer */
 					break;
@@ -742,8 +738,8 @@ PHP_FUNCTION(fbird_batch_register_blob)
 	}
 
 	/* Validate and convert BLOB ID string to ISC_QUAD */
-	if (blob_id_len != BLOB_ID_LEN || !_php_fbird_string_to_quad(blob_id_str, &existing_blob)) {
-		_php_fbird_module_error("Invalid BLOB ID format (expected %d character hex string)", BLOB_ID_LEN);
+	if ((blob_id_len != BLOB_ID_LEN && blob_id_len != BLOB_ID_LEN_LEGACY) || !_php_fbird_string_to_quad(blob_id_str, &existing_blob)) {
+		_php_fbird_module_error("Invalid BLOB ID format (expected %d or %d character hex string)", BLOB_ID_LEN, BLOB_ID_LEN_LEGACY);
 		RETURN_FALSE;
 	}
 
diff --git a/fbird_blobs.c b/fbird_blobs.c
index b9d8fd05..03e6e088 100755
--- a/fbird_blobs.c
+++ b/fbird_blobs.c
@@ -222,7 +222,7 @@ int _php_fbird_string_to_quad(char const *id, ISC_QUAD *qd)
 
 	if (sscanf(id, "%x:%x", &high_part, &low_part) == 2) {
 		qd->gds_quad_high = (ISC_LONG)high_part;
-		qd->gds_quad_low = (ISC_USHORT)low_part;
+		qd->gds_quad_low = (ISC_ULONG)low_part;
 		return 1;
 	}
 
diff --git a/fbird_query_bind.c b/fbird_query_bind.c
index 005c4786..034bc611 100755
--- a/fbird_query_bind.c
+++ b/fbird_query_bind.c
@@ -926,7 +926,7 @@ int _php_fbird_bind(fbird_query *fb_query, zval *b_vars)
 
  			convert_to_string(b_var);
 
- 			if (Z_STRLEN_P(b_var) != BLOB_ID_LEN ||
+ 			if ((Z_STRLEN_P(b_var) != BLOB_ID_LEN && Z_STRLEN_P(b_var) != BLOB_ID_LEN_LEGACY) ||
  				!_php_fbird_string_to_quad(Z_STRVAL_P(b_var), &buf[i].val.qval)) {
 
  				/* OO API only: create a blob, write the string into it, then bind by blob id (ISC_QUAD). */
@@ -1040,7 +1040,7 @@ int _php_fbird_bind(fbird_query *fb_query, zval *b_vars)
 				if (Z_TYPE_P(b_var) != IS_ARRAY) {
 					convert_to_string(b_var);
 
-					if (Z_STRLEN_P(b_var) != BLOB_ID_LEN ||
+					if ((Z_STRLEN_P(b_var) != BLOB_ID_LEN && Z_STRLEN_P(b_var) != BLOB_ID_LEN_LEGACY) ||
 						!_php_fbird_string_to_quad(Z_STRVAL_P(b_var), &buf[i].val.qval)) {
 
 						_php_fbird_module_error("Parameter %d: invalid array ID",i+1);
diff --git a/php_fbird_includes.h b/php_fbird_includes.h
index b6ce7e4d..1a1b3d31 100755
--- a/php_fbird_includes.h
+++ b/php_fbird_includes.h
@@ -319,8 +319,10 @@ ZEND_TSRMLS_CACHE_EXTERN()
  *       gds_quad_low is ISC_ULONG (32-bit unsigned) per firebird/impl/types_pub.h:194.
  *       BLOB_ID_MASK changed from %x:%hx (16-bit) to %x:%x (full 32-bit).
  *       Old 13-char IDs still parse correctly via _php_fbird_string_to_quad (uses %x:%x).
+ *       BLOB_ID_LEN_LEGACY is for backwards-compat length checks in binding paths.
  */
-#define BLOB_ID_LEN     17
+#define BLOB_ID_LEN             17
+#define BLOB_ID_LEN_LEGACY      13
 #define BLOB_ID_MASK    "%x:%x"
 
 #define BLOB_INPUT      1
diff --git a/src/Firebird/BlobId.php b/src/Firebird/BlobId.php
index 808f1fdb..f8c5ead4 100755
--- a/src/Firebird/BlobId.php
+++ b/src/Firebird/BlobId.php
@@ -106,7 +106,7 @@ private function __construct(string $id, int $high, int $low)
      * Create a BlobId from a string.
      *
      * Supports two formats:
-     * - Colon format: "HHHHHHHH:LLLL" (13 chars, standard from php-firebird extension)
+     * - Colon format: "HHHHHHHH:LLLLLLLL" (17 chars, standard from php-firebird extension)
      * - Hex format: "0xHHHHHHHHHHHHHHHH" (18 chars, legacy)
      *
      * @param string $id BLOB ID string
@@ -119,7 +119,7 @@ public static function fromString(string $id): self
 
         if (!self::isValidFormat($id)) {
             throw new InvalidArgumentException(sprintf(
-                'Invalid BLOB ID format: "%s". Expected formats: "HHHHHHHH:LLLL" or "0xHHHHHHHHHHHHHHHH".',
+                'Invalid BLOB ID format: "%s". Expected formats: "HHHHHHHH:LLLLLLLL" or "0xHHHHHHHHHHHHHHHH".',
                 strlen($id) > 30 ? substr($id, 0, 30) . '...' : $id
             ));
         }
@@ -132,12 +132,10 @@ public static function fromString(string $id): self
             $low = hexdec($lowHex);
             $normalized = sprintf('%08X:%08X', $high, $low);
         } else {
-            // Hex format: "0xHHHHHHHHHHHHHHHH"
-            // Colon format uses high 32 bits + middle 16 bits (not last 16)
+            // Hex format: "0xHHHHHHHHLLLLLLLL" (16 hex digits = 64 bits)
             $hex = substr($id, 2); // Remove "0x" prefix
-            $high = hexdec(substr($hex, 0, 8));
-            // For colon format, use middle 16 bits (positions 8-11, not 12-15)
-            $low = hexdec(substr($hex, 8, 4));
+            $high = hexdec(substr($hex, 0, 8));  // first 8 hex = high 32 bits
+            $low = hexdec(substr($hex, 8, 8));   // next 8 hex = low 32 bits
             // Normalize to colon format (standard)
             $normalized = sprintf('%08X:%08X', $high, $low);
         }
diff --git a/tests/blobid_001.phpt b/tests/blobid_001.phpt
index 7e22dd0a..93392545 100755
--- a/tests/blobid_001.phpt
+++ b/tests/blobid_001.phpt
@@ -163,7 +163,7 @@ bool(false)
 Test 10: Case insensitivity and format conversion
 bool(true)
 string(17) "abcdef01:00002345"
-string(17) "abcdef01:00002345"
+string(17) "abcdef01:23456789"
 
 Test 11: Integration with fbird_blob functions
 bool(true)