I contacted Bitmain on August 4th 2018 via their support system to request the Complete Corresponding GPL source code to the cgminer 4.9.0 mining software that they use on the Antminer Z9. They have so far failed to comply with the request and their support agent "Barbara" has only given excuses for why it hasn't been uploaded yet. Giving GitHub repository links from back in 2016!.
The GPL licenses for the cgminer require they make complete source code available at the same time as the binary:
For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable.
What they have uploaded to their GitHub so far is outdated, incomplete and is missing components necessary to compile. The GPL also requires that they provide the source code for every firmware version they release, although I only requested they provide the source code for the latest version so far.
Read more: reddit.com