Restoring an RDS Custom for SQL Server instance to a point in time

Run the following SQL script.

create table msdb..rds_pitr_blocked_databases
(
database_id INT NOT NULL,
database_name SYSNAME NOT NULL,
db_entry_updated_date datetime NOT NULL DEFAULT GETDATE(),
db_entry_updated_by SYSNAME NOT NULL DEFAULT CURRENT_USER,
PRIMARY KEY (database_id)
);

Run the following SQL script.

DECLARE @Limit INT;
SET @Limit = (insert-database-instance-limit-here);

USE msdb;
IF (EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'dbo' AND  TABLE_NAME = 'rds_pitr_blocked_databases'))
    WITH TABLE0 AS (
        SELECT hdrs.database_id as DatabaseId, sdb.name as DatabaseName, 'ALWAYS_ON_NOT_WRITABLE_REPLICA' as Reason, NULL as DatabaseNameOnPitrTable
        FROM sys.dm_hadr_database_replica_states hdrs
        INNER JOIN sys.databases sdb ON sdb.database_id = hdrs.database_id
        WHERE (hdrs.is_local = 1 AND hdrs.is_primary_replica = 0) 
        OR (sys.fn_hadr_is_primary_replica (sdb.name) = 1 AND DATABASEPROPERTYEX (sdb.name, 'Updateability') = 'READ_ONLY')
    ),
    TABLE1 as (
            SELECT dbs.database_id as DatabaseId, sysdbs.name as DatabaseName, 'OPTOUT' as Reason,
            CASE WHEN dbs.database_name = sysdbs.name THEN NULL ELSE dbs.database_name END AS DatabaseNameOnPitrTable
            FROM msdb.dbo.rds_pitr_blocked_databases dbs
            INNER JOIN sys.databases sysdbs ON dbs.database_id = sysdbs.database_id
            WHERE sysdbs.database_id > 4
            ),
    TABLE2 as (
            SELECT
            db.name AS DatabaseName,
            db.create_date AS CreateDate,
            db.state_desc AS DatabaseState,
            db.database_id AS DatabaseId,
            rs.database_guid AS DatabaseGuid,
            rs.last_log_backup_lsn AS LastLogBackupLSN,
            rs.recovery_fork_guid RecoveryForkGuid,
            rs.first_recovery_fork_guid AS FirstRecoveryForkGuid,
            db.recovery_model_desc AS RecoveryModel,
            db.is_auto_close_on AS IsAutoClose,
            db.is_read_only as IsReadOnly,
            NEWID() as FileName,
            CASE WHEN(db.state_desc = 'ONLINE'
                    AND db.recovery_model_desc != 'SIMPLE' 
                    AND((db.is_auto_close_on = 0 and db.collation_name IS NOT NULL) OR db.is_auto_close_on = 1)) 
                    AND db.is_read_only != 1
                    AND db.user_access = 0
                    AND db.source_database_id IS NULL
                    AND db.is_in_standby != 1
                    THEN 1 ELSE 0 END AS IsPartOfSnapshot,
            CASE WHEN db.source_database_id IS NULL THEN 0 ELSE 1 END AS IsDatabaseSnapshot
            FROM sys.databases db
            INNER JOIN sys.database_recovery_status rs
            ON db.database_id = rs.database_id
            WHERE DB_NAME(db.database_id) NOT IN('tempdb') AND
            db.database_id NOT IN (SELECT DISTINCT DatabaseId FROM TABLE1) AND
            db.database_id NOT IN (SELECT DISTINCT DatabaseId FROM TABLE0)
        ),
        TABLE3 as(
            Select @Limit+count(DatabaseName) as TotalNumberOfDatabases from TABLE2 where TABLE2.IsPartOfSnapshot=1 and DatabaseName in ('master','model','msdb')
        )
        SELECT TOP(SELECT TotalNumberOfDatabases from TABLE3)  DatabaseName,CreateDate,DatabaseState,DatabaseId from TABLE2 where TABLE2.IsPartOfSnapshot=1
        ORDER BY TABLE2.DatabaseID ASC
ELSE
    WITH TABLE0 AS (
        SELECT hdrs.database_id as DatabaseId, sdb.name as DatabaseName, 'ALWAYS_ON_NOT_WRITABLE_REPLICA' as Reason, NULL as DatabaseNameOnPitrTable
        FROM sys.dm_hadr_database_replica_states hdrs
        INNER JOIN sys.databases sdb ON sdb.database_id = hdrs.database_id
        WHERE (hdrs.is_local = 1 AND hdrs.is_primary_replica = 0) 
        OR (sys.fn_hadr_is_primary_replica (sdb.name) = 1 AND DATABASEPROPERTYEX (sdb.name, 'Updateability') = 'READ_ONLY')
    ),
    TABLE1 as (
            SELECT
            db.name AS DatabaseName,
            db.create_date AS CreateDate,
            db.state_desc AS DatabaseState,
            db.database_id AS DatabaseId,
            rs.database_guid AS DatabaseGuid,
            rs.last_log_backup_lsn AS LastLogBackupLSN,
            rs.recovery_fork_guid RecoveryForkGuid,
            rs.first_recovery_fork_guid AS FirstRecoveryForkGuid,
            db.recovery_model_desc AS RecoveryModel,
            db.is_auto_close_on AS IsAutoClose,
            db.is_read_only as IsReadOnly,
            NEWID() as FileName,
            CASE WHEN(db.state_desc = 'ONLINE'
                    AND db.recovery_model_desc != 'SIMPLE' 
                    AND((db.is_auto_close_on = 0 and db.collation_name IS NOT NULL) OR db.is_auto_close_on = 1)) 
                    AND db.is_read_only != 1
                    AND db.user_access = 0
                    AND db.source_database_id IS NULL
                    AND db.is_in_standby != 1
                    THEN 1 ELSE 0 END AS IsPartOfSnapshot,
            CASE WHEN db.source_database_id IS NULL THEN 0 ELSE 1 END AS IsDatabaseSnapshot
            FROM sys.databases db
            INNER JOIN sys.database_recovery_status rs
            ON db.database_id = rs.database_id
            WHERE DB_NAME(db.database_id) NOT IN('tempdb') AND
            db.database_id NOT IN (SELECT DISTINCT DatabaseId FROM TABLE0)
        ),
        TABLE2 as(
            SELECT @Limit+count(DatabaseName) as TotalNumberOfDatabases from TABLE1 where TABLE1.IsPartOfSnapshot=1 and DatabaseName in ('master','model','msdb')
        )
        select top(select TotalNumberOfDatabases from TABLE2)  DatabaseName,CreateDate,DatabaseState,DatabaseId from TABLE1 where TABLE1.IsPartOfSnapshot=1
        ORDER BY TABLE1.DatabaseID ASC