Good advice, one quibble:

> Only the copyright holder has the right to take any action against a licensee violating the terms of their license

This might not be true. If you can successfully argue that:

1. You bought the hardware because you believed their promise that you would have access to the sources they used, and

2. The value of the device is materially impaired by not having access to the source

then you would have (IMO, IANAL) a trade descriptions case. If you want to audit your phone system for security reasons, say, then the above might apply.