The PDF written offer seems to request that you send e-mail to mobile@huawei.com. Have you tried sending a request to that e-mail? Note that the GPL does not

The PDF written offer seems to request that you send e-mail to mobile@huawei.com. Have you tried sending a request to that e-mail? Note that the GPL does not require that the source code be made available on-line. If the binaries were distributed to you, the entity which distributed the binaries is obligated to send you the sources on request, but they can come on a CD, DVD, or potentially even 9-track tape.