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Suppose that I am writing the firmware F for the device D, and that I am using the library L which is licenses under GPLv2. The library L is a "source code library" that means that it is not compiled, but is composed of source code files that need to be compiled and linked with the main application.
The device D is a custom device for the customer C, so it is not meant to be sold to everybody, but only to customer C.
What am I obliged to do in this case?
Do I have to provide customer C with all of the source code of firmware F?
How am I supposed to provide this source code?