My company is designing a product based on the i.MX6 and we're considering Yocto (or Ubuntu) for the OS. I've been able to use Yocto dora to build something that runs on our custom board to test it out.
The Yocto repos are always being updated, and eventually dora will be taken down/no longer supported. At some point when our product is ready for release, we will no longer want to receive updates to Yocto or rely on its repositories; we'll want to freeze the source. We will want to be able to make changes to our application (bug fixes, etc.) but we won't want anything to change otherwise.
What's the best method of creating our own copy of Yocto that includes everything we need and doesn't rely on any of the sources being hosted externally?