I want to use a third party software C-library "A" commerially in a product "P" (in fact a firmware, running on a device).
The third party product "A" is subject to Apache 2 license. That means, I have to give a notice to the user of the final product "P" about using this open source library.
Now I have a third library "C" from a company (in fact it is a driver for a part of a microcontroller. We are allowed to use "C" internally for developing "P". We are not allowed to give away "C" to anybody else, beside of the object code generated.
Is it allowed to make adaptations of "A" in a way to call functions of "C" within "A" ?
We do not need to make our changes of "A" public, but can there be a problem?