diff --git a/ext/pdo/tests/pdo_017.phpt b/ext/pdo/tests/pdo_017.phpt
index bc514bff2c32b..d24aff1c15f32 100644
--- a/ext/pdo/tests/pdo_017.phpt
+++ b/ext/pdo/tests/pdo_017.phpt
@@ -8,7 +8,6 @@ $dir = getenv('REDIR_TEST_DIR');
 if (false == $dir) die('skip no driver');
 require_once $dir . 'pdo_test.inc';
 PDOTest::skip();
-if (str_starts_with(getenv('PDOTEST_DSN'), "firebird")) die('xfail firebird driver does not behave as expected');
 
 $db = PDOTest::factory();
 try {
diff --git a/ext/pdo_firebird/firebird_driver.c b/ext/pdo_firebird/firebird_driver.c
index cbd7ee7cfd377..4bc74ceac0d7c 100644
--- a/ext/pdo_firebird/firebird_driver.c
+++ b/ext/pdo_firebird/firebird_driver.c
@@ -28,11 +28,11 @@
 #include "ext/standard/info.h"
 #include "pdo/php_pdo.h"
 #include "pdo/php_pdo_driver.h"
+#include "pdo/php_pdo_error.h"
 #include "php_pdo_firebird.h"
 #include "php_pdo_firebird_int.h"
 
-static int firebird_alloc_prepare_stmt(pdo_dbh_t*, const zend_string*, XSQLDA*, isc_stmt_handle*,
-	HashTable*);
+static int firebird_alloc_prepare_stmt(pdo_dbh_t*, const zend_string*, XSQLDA*, isc_stmt_handle*, HashTable*);
 
 const char CHR_LETTER = 1;
 const char CHR_DIGIT = 2;
@@ -475,17 +475,14 @@ static void firebird_handle_closer(pdo_dbh_t *dbh) /* {{{ */
 {
 	pdo_firebird_db_handle *H = (pdo_firebird_db_handle *)dbh->driver_data;
 
-	if (dbh->in_txn) {
+	if (H->tr) {
 		if (dbh->auto_commit) {
-			if (isc_commit_transaction(H->isc_status, &H->tr)) {
-				RECORD_ERROR(dbh);
-			}
+			firebird_commit_transaction(dbh, false);
 		} else {
-			if (isc_rollback_transaction(H->isc_status, &H->tr)) {
-				RECORD_ERROR(dbh);
-			}
+			firebird_rollback_transaction(dbh, false);
 		}
 	}
+	H->in_manually_txn = 0;
 
 	if (isc_detach_database(H->isc_status, &H->db)) {
 		RECORD_ERROR(dbh);
@@ -647,8 +644,8 @@ static zend_long firebird_handle_doer(pdo_dbh_t *dbh, const zend_string *sql) /*
 	}
 
 	/* commit if we're in auto_commit mode */
-	if (dbh->auto_commit && isc_commit_retaining(H->isc_status, &H->tr)) {
-		RECORD_ERROR(dbh);
+	if (dbh->auto_commit && !H->in_manually_txn) {
+		firebird_commit_transaction(dbh, true);
 	}
 
 free_statement:
@@ -700,52 +697,35 @@ static zend_string* firebird_handle_quoter(pdo_dbh_t *dbh, const zend_string *un
 }
 /* }}} */
 
-/* called by PDO to start a transaction */
-static bool firebird_handle_begin(pdo_dbh_t *dbh) /* {{{ */
+/* _firebird_begin_transaction */
+static bool _firebird_begin_transaction(pdo_dbh_t *dbh) /* {{{ */
 {
 	pdo_firebird_db_handle *H = (pdo_firebird_db_handle *)dbh->driver_data;
-	char tpb[8] = { isc_tpb_version3 }, *ptpb = tpb+1;
-#ifdef abies_0
-	if (dbh->transaction_flags & PDO_TRANS_ISOLATION_LEVEL) {
-		if (dbh->transaction_flags & PDO_TRANS_READ_UNCOMMITTED) {
-			/* this is a poor fit, but it's all we have */
+	char tpb[5] = { isc_tpb_version3 }, *ptpb = tpb + strlen(tpb);
+
+	switch (H->txn_isolation_level) {
+		case PDO_FB_READ_COMMITTED:
 			*ptpb++ = isc_tpb_read_committed;
 			*ptpb++ = isc_tpb_rec_version;
-			dbh->transaction_flags &= ~(PDO_TRANS_ISOLATION_LEVEL^PDO_TRANS_READ_UNCOMMITTED);
-		} else if (dbh->transaction_flags & PDO_TRANS_READ_COMMITTED) {
-			*ptpb++ = isc_tpb_read_committed;
-			*ptpb++ = isc_tpb_no_rec_version;
-			dbh->transaction_flags &= ~(PDO_TRANS_ISOLATION_LEVEL^PDO_TRANS_READ_COMMITTED);
-		} else if (dbh->transaction_flags & PDO_TRANS_REPEATABLE_READ) {
-			*ptpb++ = isc_tpb_concurrency;
-			dbh->transaction_flags &= ~(PDO_TRANS_ISOLATION_LEVEL^PDO_TRANS_REPEATABLE_READ);
-		} else {
+			break;
+
+		case PDO_FB_SERIALIZABLE:
 			*ptpb++ = isc_tpb_consistency;
-			dbh->transaction_flags &= ~(PDO_TRANS_ISOLATION_LEVEL^PDO_TRANS_SERIALIZABLE);
-		}
-	}
+			break;
 
-	if (dbh->transaction_flags & PDO_TRANS_ACCESS_MODE) {
-		if (dbh->transaction_flags & PDO_TRANS_READONLY) {
-			*ptpb++ = isc_tpb_read;
-			dbh->transaction_flags &= ~(PDO_TRANS_ACCESS_MODE^PDO_TRANS_READONLY);
-		} else {
-			*ptpb++ = isc_tpb_write;
-			dbh->transaction_flags &= ~(PDO_TRANS_ACCESS_MODE^PDO_TRANS_READWRITE);
-		}
+		case PDO_FB_REPEATABLE_READ:
+		default:
+			*ptpb++ = isc_tpb_concurrency;
+			break;
 	}
 
-	if (dbh->transaction_flags & PDO_TRANS_CONFLICT_RESOLUTION) {
-		if (dbh->transaction_flags & PDO_TRANS_RETRY) {
-			*ptpb++ = isc_tpb_wait;
-			dbh->transaction_flags &= ~(PDO_TRANS_CONFLICT_RESOLUTION^PDO_TRANS_RETRY);
-		} else {
-			*ptpb++ = isc_tpb_nowait;
-			dbh->transaction_flags &= ~(PDO_TRANS_CONFLICT_RESOLUTION^PDO_TRANS_ABORT);
-		}
+	if (H->is_writable_txn) {
+		*ptpb++ = isc_tpb_write;
+	} else {
+		*ptpb++ = isc_tpb_read;
 	}
-#endif
-	if (isc_start_transaction(H->isc_status, &H->tr, 1, &H->db, (unsigned short)(ptpb-tpb), tpb)) {
+
+	if (isc_start_transaction(H->isc_status, &H->tr, 1, &H->db, (unsigned short)(ptpb - tpb), tpb)) {
 		RECORD_ERROR(dbh);
 		return false;
 	}
@@ -753,28 +733,90 @@ static bool firebird_handle_begin(pdo_dbh_t *dbh) /* {{{ */
 }
 /* }}} */
 
+/* called by PDO to start a transaction */
+static bool firebird_handle_manually_begin(pdo_dbh_t *dbh) /* {{{ */
+{
+	pdo_firebird_db_handle *H = (pdo_firebird_db_handle *)dbh->driver_data;
+
+	if (dbh->auto_commit && H->tr && !firebird_commit_transaction(dbh, false)) {
+		return false;
+	}
+
+	if (!_firebird_begin_transaction(dbh)) {
+		return false;
+	}
+
+	H->in_manually_txn = 1;
+	return true;
+}
+/* }}} */
+
+/* firebird_commit_transaction */
+bool _firebird_commit_transaction(pdo_dbh_t *dbh, bool retain) /* {{{ */
+{
+	pdo_firebird_db_handle *H = (pdo_firebird_db_handle *)dbh->driver_data;
+
+	if (retain) {
+		if (isc_commit_retaining(H->isc_status, &H->tr)) {
+			RECORD_ERROR(dbh);
+			return false;
+		}
+	} else {
+		if (isc_commit_transaction(H->isc_status, &H->tr)) {
+			RECORD_ERROR(dbh);
+			return false;
+		}
+	}
+
+	return true;
+}
+/* }}} */
+
 /* called by PDO to commit a transaction */
-static bool firebird_handle_commit(pdo_dbh_t *dbh) /* {{{ */
+static bool firebird_handle_manually_commit(pdo_dbh_t *dbh) /* {{{ */
 {
 	pdo_firebird_db_handle *H = (pdo_firebird_db_handle *)dbh->driver_data;
 
-	if (isc_commit_transaction(H->isc_status, &H->tr)) {
-		RECORD_ERROR(dbh);
+	if (!firebird_commit_transaction(dbh, dbh->auto_commit)) {
 		return false;
 	}
+
+	H->in_manually_txn = 0;
+	return true;
+}
+/* }}} */
+
+/* firebird_rollback_transaction */
+bool _firebird_rollback_transaction(pdo_dbh_t *dbh, bool retain) /* {{{ */
+{
+	pdo_firebird_db_handle *H = (pdo_firebird_db_handle *)dbh->driver_data;
+
+	if (retain) {
+		if (isc_rollback_retaining(H->isc_status, &H->tr)) {
+			RECORD_ERROR(dbh);
+			return false;
+		}
+	} else {
+		if (isc_rollback_transaction(H->isc_status, &H->tr)) {
+			RECORD_ERROR(dbh);
+			return false;
+		}
+	}
+
 	return true;
 }
 /* }}} */
 
 /* called by PDO to rollback a transaction */
-static bool firebird_handle_rollback(pdo_dbh_t *dbh) /* {{{ */
+static bool firebird_handle_manually_rollback(pdo_dbh_t *dbh) /* {{{ */
 {
 	pdo_firebird_db_handle *H = (pdo_firebird_db_handle *)dbh->driver_data;
 
-	if (isc_rollback_transaction(H->isc_status, &H->tr)) {
-		RECORD_ERROR(dbh);
+	if (!firebird_rollback_transaction(dbh, dbh->auto_commit)) {
 		return false;
 	}
+
+	H->in_manually_txn = 0;
 	return true;
 }
 /* }}} */
@@ -792,16 +834,6 @@ static int firebird_alloc_prepare_stmt(pdo_dbh_t *dbh, const zend_string *sql,
 		return 0;
 	}
 
-	/* start a new transaction implicitly if auto_commit is enabled and no transaction is open */
-	if (dbh->auto_commit && !dbh->in_txn) {
-		/* dbh->transaction_flags = PDO_TRANS_READ_UNCOMMITTED; */
-
-		if (!firebird_handle_begin(dbh)) {
-			return 0;
-		}
-		dbh->in_txn = true;
-	}
-
 	/* allocate the statement */
 	if (isc_dsql_allocate_statement(H->isc_status, &H->db, s)) {
 		RECORD_ERROR(dbh);
@@ -834,6 +866,7 @@ static bool firebird_handle_set_attribute(pdo_dbh_t *dbh, zend_long attr, zval *
 {
 	pdo_firebird_db_handle *H = (pdo_firebird_db_handle *)dbh->driver_data;
 	bool bval;
+	zend_long lval;
 
 	switch (attr) {
 		case PDO_ATTR_AUTOCOMMIT:
@@ -844,19 +877,22 @@ static bool firebird_handle_set_attribute(pdo_dbh_t *dbh, zend_long attr, zval *
 
 				/* ignore if the new value equals the old one */
 				if (dbh->auto_commit ^ bval) {
-					if (dbh->in_txn) {
-						if (bval) {
+					if (bval) {
+						if (H->tr && H->in_manually_txn) {
 							/* turning on auto_commit with an open transaction is illegal, because
-							   we won't know what to do with it */
+							we won't know what to do with it */
 							H->last_app_error = "Cannot enable auto-commit while a transaction is already open";
 							return false;
-						} else {
-							/* close the transaction */
-							if (!firebird_handle_commit(dbh)) {
-								break;
-							}
-							dbh->in_txn = false;
 						}
+						if (!H->tr && !_firebird_begin_transaction(dbh)) {
+							return false;
+						}
+					} else {
+						/* close the transaction */
+						if (H->tr && !firebird_commit_transaction(dbh, false)) {
+							return false;
+						}
+						H->in_manually_txn = 0;
 					}
 					dbh->auto_commit = bval;
 				}
@@ -911,6 +947,60 @@ static bool firebird_handle_set_attribute(pdo_dbh_t *dbh, zend_long attr, zval *
 				zend_string_release_ex(str, 0);
 			}
 			return true;
+
+		case PDO_FB_TRANSACTION_ISOLATION_LEVEL:
+			{
+				if (!pdo_get_long_param(&lval, val)) {
+					return false;
+				}
+				if (H->txn_isolation_level != lval) {
+					if (lval == PDO_FB_READ_COMMITTED ||
+						lval == PDO_FB_REPEATABLE_READ ||
+						lval == PDO_FB_SERIALIZABLE
+					) {
+						if (H->tr && H->in_manually_txn) {
+							H->last_app_error = "Cannot change isolation level while a transaction is already open";
+							return false;
+						}
+						H->txn_isolation_level = lval;
+						if (dbh->auto_commit) {
+							if (H->tr && !firebird_commit_transaction(dbh, false)) {
+								return false;
+							}
+							if (!_firebird_begin_transaction(dbh)) {
+								return false;
+							}
+						}
+					} else {
+						return false;
+					}
+				}
+			}
+			return true;
+
+		case PDO_FB_WRITABLE_TRANSACTION:
+			{
+				if (!pdo_get_bool_param(&bval, val)) {
+					return false;
+				}
+
+				if (H->is_writable_txn != bval) {
+					if (H->tr && H->in_manually_txn) {
+						H->last_app_error = "Cannot change access mode while a transaction is already open";
+						return false;
+					}
+					H->is_writable_txn = bval;
+					if (dbh->auto_commit) {
+						if (H->tr && !firebird_commit_transaction(dbh, false)) {
+							return false;
+						}
+						if (!_firebird_begin_transaction(dbh)) {
+							return false;
+						}
+					}
+				}
+			}
+			return true;
 	}
 	return false;
 }
@@ -983,6 +1073,14 @@ static int firebird_handle_get_attribute(pdo_dbh_t *dbh, zend_long attr, zval *v
 		case PDO_ATTR_FETCH_TABLE_NAMES:
 			ZVAL_BOOL(val, H->fetch_table_names);
 			return 1;
+
+		case PDO_FB_TRANSACTION_ISOLATION_LEVEL:
+			ZVAL_LONG(val, H->txn_isolation_level);
+			return 1;
+
+		case PDO_FB_WRITABLE_TRANSACTION:
+			ZVAL_BOOL(val, H->is_writable_txn);
+			return 1;
 	}
 	return 0;
 }
@@ -1011,14 +1109,22 @@ static void pdo_firebird_fetch_error_func(pdo_dbh_t *dbh, pdo_stmt_t *stmt, zval
 }
 /* }}} */
 
+/* {{{ firebird_in_manually_transaction */
+static bool firebird_in_manually_transaction(pdo_dbh_t *dbh)
+{
+	pdo_firebird_db_handle *H = (pdo_firebird_db_handle *)dbh->driver_data;
+	return H->tr && H->in_manually_txn;
+}
+/* }}} */
+
 static const struct pdo_dbh_methods firebird_methods = { /* {{{ */
 	firebird_handle_closer,
 	firebird_handle_preparer,
 	firebird_handle_doer,
 	firebird_handle_quoter,
-	firebird_handle_begin,
-	firebird_handle_commit,
-	firebird_handle_rollback,
+	firebird_handle_manually_begin,
+	firebird_handle_manually_commit,
+	firebird_handle_manually_rollback,
 	firebird_handle_set_attribute,
 	NULL, /* last_id not supported */
 	pdo_firebird_fetch_error_func,
@@ -1026,7 +1132,7 @@ static const struct pdo_dbh_methods firebird_methods = { /* {{{ */
 	NULL, /* check_liveness */
 	NULL, /* get driver methods */
 	NULL, /* request shutdown */
-	NULL, /* in transaction, use PDO's internal tracking mechanism */
+	firebird_in_manually_transaction,
 	NULL /* get gc */
 };
 /* }}} */
@@ -1057,6 +1163,23 @@ static int pdo_firebird_handle_factory(pdo_dbh_t *dbh, zval *driver_options) /*
 		dbh->password = pestrdup(vars[5].optval, dbh->is_persistent);
 	}
 
+	H->in_manually_txn = 0;
+	if (driver_options) {
+		H->is_writable_txn = pdo_attr_lval(driver_options, PDO_FB_WRITABLE_TRANSACTION, 1);
+		zend_long txn_isolation_level = pdo_attr_lval(driver_options, PDO_FB_TRANSACTION_ISOLATION_LEVEL, PDO_FB_REPEATABLE_READ);
+		if (txn_isolation_level == PDO_FB_READ_COMMITTED ||
+			txn_isolation_level == PDO_FB_REPEATABLE_READ ||
+			txn_isolation_level == PDO_FB_SERIALIZABLE
+		) {
+			H->txn_isolation_level = txn_isolation_level;
+		} else {
+			H->txn_isolation_level = PDO_FB_REPEATABLE_READ;
+		}
+	} else {
+		H->is_writable_txn = 1;
+		H->txn_isolation_level = PDO_FB_REPEATABLE_READ;
+	}
+
 	do {
 		static char const dpb_flags[] = {
 			isc_dpb_user_name, isc_dpb_password, isc_dpb_lc_ctype, isc_dpb_sql_role_name };
@@ -1107,6 +1230,10 @@ static int pdo_firebird_handle_factory(pdo_dbh_t *dbh, zval *driver_options) /*
 				"HY000", H->isc_status[1], errmsg);
 	}
 
+	if (dbh->auto_commit && !H->tr) {
+		ret = _firebird_begin_transaction(dbh);
+	}
+
 	if (!ret) {
 		firebird_handle_closer(dbh);
 	}
diff --git a/ext/pdo_firebird/firebird_statement.c b/ext/pdo_firebird/firebird_statement.c
index 4ad51ab483d96..f0d43bbddb29b 100644
--- a/ext/pdo_firebird/firebird_statement.c
+++ b/ext/pdo_firebird/firebird_statement.c
@@ -177,8 +177,7 @@ static int firebird_stmt_execute(pdo_stmt_t *stmt) /* {{{ */
 				;
 		}
 
-		/* commit? */
-		if (stmt->dbh->auto_commit && isc_commit_retaining(H->isc_status, &H->tr)) {
+		if (stmt->dbh->auto_commit && !S->H->in_manually_txn && !firebird_commit_transaction(stmt->dbh, true)) {
 			break;
 		}
 
diff --git a/ext/pdo_firebird/pdo_firebird.c b/ext/pdo_firebird/pdo_firebird.c
index efbebccb0e127..35cbfb51d9a06 100644
--- a/ext/pdo_firebird/pdo_firebird.c
+++ b/ext/pdo_firebird/pdo_firebird.c
@@ -57,6 +57,11 @@ PHP_MINIT_FUNCTION(pdo_firebird) /* {{{ */
 	REGISTER_PDO_CLASS_CONST_LONG("FB_ATTR_DATE_FORMAT", (zend_long) PDO_FB_ATTR_DATE_FORMAT);
 	REGISTER_PDO_CLASS_CONST_LONG("FB_ATTR_TIME_FORMAT", (zend_long) PDO_FB_ATTR_TIME_FORMAT);
 	REGISTER_PDO_CLASS_CONST_LONG("FB_ATTR_TIMESTAMP_FORMAT", (zend_long) PDO_FB_ATTR_TIMESTAMP_FORMAT);
+	REGISTER_PDO_CLASS_CONST_LONG("FB_TRANSACTION_ISOLATION_LEVEL", (zend_long) PDO_FB_TRANSACTION_ISOLATION_LEVEL);
+	REGISTER_PDO_CLASS_CONST_LONG("FB_READ_COMMITTED", (zend_long) PDO_FB_READ_COMMITTED);
+	REGISTER_PDO_CLASS_CONST_LONG("FB_REPEATABLE_READ", (zend_long) PDO_FB_REPEATABLE_READ);
+	REGISTER_PDO_CLASS_CONST_LONG("FB_SERIALIZABLE", (zend_long) PDO_FB_SERIALIZABLE);
+	REGISTER_PDO_CLASS_CONST_LONG("FB_WRITABLE_TRANSACTION", (zend_long) PDO_FB_WRITABLE_TRANSACTION);
 
 	if (FAILURE == php_pdo_register_driver(&pdo_firebird_driver)) {
 		return FAILURE;
diff --git a/ext/pdo_firebird/php_pdo_firebird_int.h b/ext/pdo_firebird/php_pdo_firebird_int.h
index 243163b8a08ad..7f0664ca0a280 100644
--- a/ext/pdo_firebird/php_pdo_firebird_int.h
+++ b/ext/pdo_firebird/php_pdo_firebird_int.h
@@ -59,6 +59,12 @@ typedef void (*info_func_t)(char*);
 # define PDO_FIREBIRD_HANDLE_INITIALIZER NULL
 #endif
 
+extern bool _firebird_commit_transaction(pdo_dbh_t *dbh, bool retain);
+#define firebird_commit_transaction(d,r) _firebird_commit_transaction(d, r)
+
+extern bool _firebird_rollback_transaction(pdo_dbh_t *dbh, bool retain);
+#define firebird_rollback_transaction(d,r) _firebird_rollback_transaction(d, r)
+
 typedef struct {
 
 	/* the result of the last API call */
@@ -69,6 +75,8 @@ typedef struct {
 
 	/* the transaction handle */
 	isc_tr_handle tr;
+	bool in_manually_txn:1;
+	bool is_writable_txn:1;
 
 	/* the last error that didn't come from the API */
 	char const *last_app_error;
@@ -85,6 +93,8 @@ typedef struct {
 
 	unsigned _reserved:29;
 
+	/* transaction isolation level */
+	zend_ulong txn_isolation_level;
 } pdo_firebird_db_handle;
 
 
@@ -131,6 +141,15 @@ enum {
 	PDO_FB_ATTR_DATE_FORMAT = PDO_ATTR_DRIVER_SPECIFIC,
 	PDO_FB_ATTR_TIME_FORMAT,
 	PDO_FB_ATTR_TIMESTAMP_FORMAT,
+
+	/* transaction isolation level */
+	PDO_FB_TRANSACTION_ISOLATION_LEVEL,
+	PDO_FB_READ_COMMITTED,
+	PDO_FB_REPEATABLE_READ,
+	PDO_FB_SERIALIZABLE,
+
+	/** transaction access mode */
+	PDO_FB_WRITABLE_TRANSACTION,
 };
 
 #endif	/* PHP_PDO_FIREBIRD_INT_H */
diff --git a/ext/pdo_firebird/tests/bug_47415.phpt b/ext/pdo_firebird/tests/bug_47415.phpt
index 8349a1d50fe5d..9fb5eb660f791 100644
--- a/ext/pdo_firebird/tests/bug_47415.phpt
+++ b/ext/pdo_firebird/tests/bug_47415.phpt
@@ -15,8 +15,6 @@ $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
 $dbh->exec('CREATE TABLE test47415 (idx int NOT NULL PRIMARY KEY, txt VARCHAR(20))');
 $dbh->exec('INSERT INTO test47415 VALUES(0, \'String0\')');
 
-$dbh->commit();
-
 $query = "SELECT idx, txt FROM test47415 ORDER by idx";
 $idx = $txt = 0;
 $stmt = $dbh->prepare($query);
@@ -31,8 +29,6 @@ var_dump($stmt->rowCount());
 $stmt = $dbh->prepare('DELETE FROM test47415');
 $stmt->execute();
 
-$dbh->commit();
-
 unset($stmt);
 unset($dbh);
 ?>
diff --git a/ext/pdo_firebird/tests/bug_48877.phpt b/ext/pdo_firebird/tests/bug_48877.phpt
index e3cb6e93518d8..4415b24ad8c7f 100644
--- a/ext/pdo_firebird/tests/bug_48877.phpt
+++ b/ext/pdo_firebird/tests/bug_48877.phpt
@@ -17,7 +17,6 @@ $dbh->exec('CREATE TABLE test48877 (A integer)');
 $dbh->exec("INSERT INTO test48877 VALUES ('1')");
 $dbh->exec("INSERT INTO test48877 VALUES ('2')");
 $dbh->exec("INSERT INTO test48877 VALUES ('3')");
-$dbh->commit();
 
 $query = "SELECT * FROM test48877 WHERE A = :paramno";
 
@@ -32,7 +31,6 @@ var_dump($stmt->rowCount());
 $stmt = $dbh->prepare('DELETE FROM test48877');
 $stmt->execute();
 
-$dbh->commit();
 unset($stmt);
 unset($dbh);
 
diff --git a/ext/pdo_firebird/tests/bug_53280.phpt b/ext/pdo_firebird/tests/bug_53280.phpt
index 2a4c19a44aa8c..d8615cb03a9d4 100644
--- a/ext/pdo_firebird/tests/bug_53280.phpt
+++ b/ext/pdo_firebird/tests/bug_53280.phpt
@@ -13,7 +13,6 @@ require("testdb.inc");
 
 $dbh->exec('CREATE TABLE test53280(A VARCHAR(30), B VARCHAR(30), C VARCHAR(30))');
 $dbh->exec("INSERT INTO test53280 VALUES ('A', 'B', 'C')");
-$dbh->commit();
 
 $stmt1 = "SELECT B FROM test53280 WHERE A = ? AND B = ?";
 $stmt2 = "SELECT B, C FROM test53280 WHERE A = ? AND B = ?";
@@ -28,7 +27,6 @@ $stmth1->execute(array('A', 'B'));
 $rows = $stmth1->fetchAll(); // <------- segfault
 var_dump($rows);
 
-$dbh->commit();
 unset($stmth1);
 unset($stmth2);
 unset($stmt);
diff --git a/ext/pdo_firebird/tests/bug_62024.phpt b/ext/pdo_firebird/tests/bug_62024.phpt
index e46fad61fdad8..2c351421d26c6 100644
--- a/ext/pdo_firebird/tests/bug_62024.phpt
+++ b/ext/pdo_firebird/tests/bug_62024.phpt
@@ -14,8 +14,6 @@ require("testdb.inc");
 $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
 $dbh->exec("CREATE TABLE test62024 (ID INTEGER NOT NULL, TEXT VARCHAR(10))");
 
-$dbh->commit();
-
 //start actual test
 
 $sql = "insert into test62024 (id, text) values (?, ?)";
@@ -30,15 +28,11 @@ var_dump($res);
 $res = $sttmt->execute($args_err);
 var_dump($res);
 
-$dbh->commit();
-
 
 //teardown test data
 $sttmt = $dbh->prepare('DELETE FROM test62024');
 $sttmt->execute();
 
-$dbh->commit();
-
 unset($sttmt);
 unset($dbh);
 
diff --git a/ext/pdo_firebird/tests/bug_64037.phpt b/ext/pdo_firebird/tests/bug_64037.phpt
index a86fe5f10914e..f1034a4dacef9 100644
--- a/ext/pdo_firebird/tests/bug_64037.phpt
+++ b/ext/pdo_firebird/tests/bug_64037.phpt
@@ -17,8 +17,6 @@ $dbh->exec("INSERT INTO test64037 (ID, TEXT, COST) VALUES (1, 'test', -1.0)");
 $dbh->exec("INSERT INTO test64037 (ID, TEXT, COST) VALUES (2, 'test', -0.99)");
 $dbh->exec("INSERT INTO test64037 (ID, TEXT, COST) VALUES (3, 'test', -1.01)");
 
-$dbh->commit();
-
 $query = "SELECT * from test64037 order by ID";
 $stmt = $dbh->prepare($query);
 $stmt->execute();
@@ -31,8 +29,6 @@ var_dump($rows[2]['COST']);
 $stmt = $dbh->prepare('DELETE FROM test64037');
 $stmt->execute();
 
-$dbh->commit();
-
 unset($stmt);
 unset($dbh);
 
diff --git a/ext/pdo_firebird/tests/ddl2.phpt b/ext/pdo_firebird/tests/ddl2.phpt
new file mode 100644
index 0000000000000..5b46e60c999f5
--- /dev/null
+++ b/ext/pdo_firebird/tests/ddl2.phpt
@@ -0,0 +1,36 @@
+--TEST--
+PDO_Firebird: DDL/transactions 2
+--EXTENSIONS--
+pdo_firebird
+--SKIPIF--
+<?php require('skipif.inc'); ?>
+--ENV--
+LSAN_OPTIONS=detect_leaks=0
+--FILE--
+<?php
+require("testdb.inc");
+
+$dbh->exec("CREATE TABLE test_ddl2 (val int)");
+
+$dbh->beginTransaction();
+$dbh->exec("INSERT INTO test_ddl2 (val) VALUES (120)");
+$dbh->exec("CREATE TABLE test_ddl2_2 (val INT)");
+$dbh->rollback();
+
+$result = $dbh->query("SELECT * FROM test_ddl2");
+foreach ($result as $r) {
+    var_dump($r);
+}
+
+unset($dbh);
+echo "done\n";
+?>
+--CLEAN--
+<?php
+require("testdb.inc");
+$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
+@$dbh->exec('DROP TABLE test_ddl2');
+@$dbh->exec('DROP TABLE test_ddl2_2');
+?>
+--EXPECT--
+done
diff --git a/ext/pdo_firebird/tests/payload_test.phpt b/ext/pdo_firebird/tests/payload_test.phpt
index 0638e47e7e13f..e093d5a831763 100644
--- a/ext/pdo_firebird/tests/payload_test.phpt
+++ b/ext/pdo_firebird/tests/payload_test.phpt
@@ -16,6 +16,9 @@ $dsn = "firebird:dbname=inet://$address/test";
 $username = 'SYSDBA';
 $password = 'masterkey';
 
-new PDO($dsn, $username, $password, [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]);
+new PDO($dsn, $username, $password, [
+    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
+    PDO::ATTR_AUTOCOMMIT => false,
+]);
 ?>
 --EXPECT--
diff --git a/ext/pdo_firebird/tests/rowCount.phpt b/ext/pdo_firebird/tests/rowCount.phpt
index bf3a9be0b49de..5604223ec4cc3 100644
--- a/ext/pdo_firebird/tests/rowCount.phpt
+++ b/ext/pdo_firebird/tests/rowCount.phpt
@@ -15,7 +15,6 @@ $dbh->exec('CREATE TABLE test_rowcount (A VARCHAR(10))');
 $dbh->exec("INSERT INTO test_rowcount VALUES ('A')");
 $dbh->exec("INSERT INTO test_rowcount VALUES ('A')");
 $dbh->exec("INSERT INTO test_rowcount VALUES ('B')");
-$dbh->commit();
 
 $query = "SELECT * FROM test_rowcount WHERE A = ?";
 
@@ -29,14 +28,11 @@ var_dump($stmt->rowCount());
 $stmt = $dbh->prepare('UPDATE test_rowcount SET A="A" WHERE A != ?');
 $stmt->execute(array('A'));
 var_dump($stmt->rowCount());
-$dbh->commit();
 
 $stmt = $dbh->prepare('DELETE FROM test_rowcount');
 $stmt->execute();
 var_dump($stmt->rowCount());
 
-$dbh->commit();
-
 unset($stmt);
 unset($dbh);
 
diff --git a/ext/pdo_firebird/tests/transaction_access_mode.phpt b/ext/pdo_firebird/tests/transaction_access_mode.phpt
new file mode 100644
index 0000000000000..3c9d41c5c53e9
--- /dev/null
+++ b/ext/pdo_firebird/tests/transaction_access_mode.phpt
@@ -0,0 +1,114 @@
+--TEST--
+PDO_Firebird: transaction access mode
+--EXTENSIONS--
+pdo_firebird
+--SKIPIF--
+<?php require('skipif.inc'); ?>
+--ENV--
+LSAN_OPTIONS=detect_leaks=0
+--FILE--
+<?php
+
+require("testdb.inc");
+unset($dbh);
+
+$table = 'transaction_access_mode';
+
+$values = [
+    ['val' => true, 'label' => 'writable'],
+    ['val' => false, 'label' => 'readonly'],
+];
+
+echo "Set attr in construct\n";
+
+foreach ($values as $value) {
+    $dbh = new PDO(
+        PDO_FIREBIRD_TEST_DSN,
+        PDO_FIREBIRD_TEST_USER,
+        PDO_FIREBIRD_TEST_PASS,
+        [
+            PDO::FB_WRITABLE_TRANSACTION => $value['val'],
+        ],
+    );
+
+    if ($dbh->getAttribute(PDO::FB_WRITABLE_TRANSACTION) === $value['val']) {
+        echo "OK: {$value['label']}\n";
+    } else {
+        echo "NG: {$value['label']}\n";
+    }
+
+    unset($dbh);
+}
+
+echo "\n";
+echo "Set attr in setAttribute and behavior check\n";
+
+$dbh = new PDO(
+    PDO_FIREBIRD_TEST_DSN,
+    PDO_FIREBIRD_TEST_USER,
+    PDO_FIREBIRD_TEST_PASS,
+);
+
+$dbh->query("CREATE TABLE {$table} (val int)");
+
+var_dump($dbh->setAttribute(PDO::FB_WRITABLE_TRANSACTION, true));
+
+if ($dbh->getAttribute(PDO::FB_WRITABLE_TRANSACTION) === true) {
+    echo "OK: writable\n";
+} else {
+    echo "NG: writable\n";
+}
+$dbh->query("INSERT INTO {$table} VALUES (12)");
+$r = $dbh->query("SELECT * FROM {$table}");
+foreach ($r as $row) {
+    var_dump($row);
+}
+
+var_dump($dbh->setAttribute(PDO::FB_WRITABLE_TRANSACTION, false));
+
+if ($dbh->getAttribute(PDO::FB_WRITABLE_TRANSACTION) === false) {
+    echo "OK: readonly\n";
+} else {
+    echo "NG: readonly\n";
+}
+try {
+    $dbh->query("INSERT INTO {$table} VALUES (19)");
+} catch (PDOException $e) {
+    echo "error with readonly\n";
+}
+$r = $dbh->query("SELECT * FROM {$table}");
+foreach ($r as $row) {
+    var_dump($row);
+}
+
+unset($dbh);
+?>
+--CLEAN--
+<?php
+require 'testdb.inc';
+@$dbh->exec('DROP TABLE transaction_access_mode');
+unset($dbh);
+?>
+--EXPECT--
+Set attr in construct
+OK: writable
+OK: readonly
+
+Set attr in setAttribute and behavior check
+bool(true)
+OK: writable
+array(2) {
+  ["VAL"]=>
+  int(12)
+  [0]=>
+  int(12)
+}
+bool(true)
+OK: readonly
+error with readonly
+array(2) {
+  ["VAL"]=>
+  int(12)
+  [0]=>
+  int(12)
+}
diff --git a/ext/pdo_firebird/tests/transaction_isolation_level.phpt b/ext/pdo_firebird/tests/transaction_isolation_level.phpt
new file mode 100644
index 0000000000000..0a6ed41e43fb4
--- /dev/null
+++ b/ext/pdo_firebird/tests/transaction_isolation_level.phpt
@@ -0,0 +1,78 @@
+--TEST--
+PDO_Firebird: transaction isolation level
+--EXTENSIONS--
+pdo_firebird
+--SKIPIF--
+<?php require('skipif.inc'); ?>
+--ENV--
+LSAN_OPTIONS=detect_leaks=0
+--FILE--
+<?php
+
+require("testdb.inc");
+unset($dbh);
+
+$levelStrs = [
+    'PDO::FB_READ_COMMITTED',
+    'PDO::FB_REPEATABLE_READ',
+    'PDO::FB_SERIALIZABLE',
+];
+
+echo "Set attr in construct\n";
+
+foreach ($levelStrs as $levelStr) {
+    $level = constant($levelStr);
+    $dbh = new PDO(
+        PDO_FIREBIRD_TEST_DSN,
+        PDO_FIREBIRD_TEST_USER,
+        PDO_FIREBIRD_TEST_PASS,
+        [
+            PDO::FB_TRANSACTION_ISOLATION_LEVEL => $level,
+        ],
+    );
+
+    if ($dbh->getAttribute(PDO::FB_TRANSACTION_ISOLATION_LEVEL) === $level) {
+        echo "OK: {$levelStr}\n";
+    } else {
+        echo "NG: {$levelStr}\n";
+    }
+
+    unset($dbh);
+}
+
+echo "\n";
+echo "Set attr in setAttribute\n";
+
+$dbh = new PDO(
+    PDO_FIREBIRD_TEST_DSN,
+    PDO_FIREBIRD_TEST_USER,
+    PDO_FIREBIRD_TEST_PASS,
+);
+
+foreach ($levelStrs as $levelStr) {
+    $level = constant($levelStr);
+
+    var_dump($dbh->setAttribute(PDO::FB_TRANSACTION_ISOLATION_LEVEL, $level));
+
+    if ($dbh->getAttribute(PDO::FB_TRANSACTION_ISOLATION_LEVEL) === $level) {
+        echo "OK: {$levelStr}\n";
+    } else {
+        echo "NG: {$levelStr}\n";
+    }
+}
+
+unset($dbh);
+?>
+--EXPECT--
+Set attr in construct
+OK: PDO::FB_READ_COMMITTED
+OK: PDO::FB_REPEATABLE_READ
+OK: PDO::FB_SERIALIZABLE
+
+Set attr in setAttribute
+bool(true)
+OK: PDO::FB_READ_COMMITTED
+bool(true)
+OK: PDO::FB_REPEATABLE_READ
+bool(true)
+OK: PDO::FB_SERIALIZABLE