Looked this up on their forum — not sure if any actual developers responded to the questions but whoever responded there is a bunch of pussies. "Oh, but why would you do this if your IMSI/MSISDN/ICCID are still the same?" "Oh, it's illegal" "Oh, use a Mudi router with a blue-merle opkg to randomize IMEIs" etc.
No real answers.
But then, I found the official response, and it's quite silly, to put it mildly:
> Spoofing the IMEI shown in the OS is not changing the IMEI used for cellular, and is not useful beyond fooling yourself. Changing the IMEI used for cellular is not possible with modern cellular radios, which are required by regulations to prevent changing it. Changing it requires a cellular radio exploit, which would imply not patching the radio or using a device with an insecure cellular radio. Changing the IMEI doesn't provide anonymity. There are multiple other hardware identifiers.
What planet do these guys live on? "Changing the IMEI used for cellular is not possible with modern cellular radios, which are required by regulations to prevent changing it"? Really? All big three of baseband vendors (Qualcomm, MediaTek, Unisoc) don't seem to give a fuck about those regulations and rely on "security through obscurity" instead. I doubt that whoever is behind Google Tensor does any different regarding hardware identifiers, as this would increase their production costs. They might, however, place them in some qfuse-like OTP area, I can neither confirm nor deny that as of now.
By the way, some carriers do show you which IMEI (or, rather, phone model) they see in their personal cellular account page. You can easily verify who's been fooled in this case.
I won't join the #GrapheneOS forum unless I really have to, but whatever they wrote on this topic looks like deliberate or accidental misinformation. The only relief I feel at this point is that if this is an official answer, then there's 90% probability this just was not researched well enough for Tensor-based Pixels. Just give me root and enough time to find out the truth.