Apparently I can't post 81 pages of legalese in this thread, but go actually read the DMCA exemption that specifically allows hacking your car.
https://copyright.gov/1201/2015/fedreg-publicinspectionFR.pdf
The DMCA categorically doesn't apply.
It's not that I'm not reading. I am. This is 100% legal in every jurisdiction I'm aware of, and nobody has yet provided any law that says otherwise.
Not seeing where it doesn't apply. Here is the actual exemption on page 43:
"Computer programs that are contained in and control the functioning of a motorized land vehicle such as a personal automobile, commercial motor vehicle or mechanized agricultural vehicle,
except for computer programs primarily designed for the
control of telematics or entertainment systems for such vehicle,
when circumvention is a necessary step undertaken by the authorized owner of the vehicle to allow the diagnosis, repair or lawful modification of a vehicle function; and where such circumvention does not constitute a violation of applicable law, including without limitation regulations promulgated by the Department of Transportation or the Environmental Protection Agency; and provided, however, that such circumvention is initiated no earlier than 12 months after the effective date of this regulation."
First thing that sticks out is that this exemption does not apply to telematics (navigation being the most obvious example, but autopilot uses almost every aspect of telematics).
Moving on: the suggested changes are obviously not to allow diagnosis or repair, so it falls on what that exemption means by "to allow ... lawful modification of a vehicle function".
Page 40 clarifies:
"Proponents explained that circumvention of TPMs protecting copyrighted computer programs in ECUs may be necessary to make noninfringing uses of those programs to diagnose and repair automobiles and agricultural equipment, and
to make modifications, such as enhancing a vehicle’s suspension or installing a gear with a different radius. They assert that vehicle owners are entitled to use the computer programs in ECUs to diagnose, repair or
modify vehicles as a matter of fair use, or under section 117."
So this exemption covers tampering of the ECU in order to enable other modifications (like ECU adjustments to account for a custom suspension or different gear ratio). The main purpose is to allow lawful fair use. I don't see how unlocking paid features falls under this. That's my analysis, again with the huge caveut of IANAL.
Second exemption:
"(i) Computer programs, where the circumvention is undertaken on a lawfully acquired device or machine on which the computer program operates solely for the purpose of
good-faith security research and does not violate any applicable law, including without limitation the Computer Fraud and Abuse Act of 1986, as amended and codified in title 18, United States Code; and provided, however, that, except as to voting machines, such circumvention is initiated no earlier than 12 months after the effective date of this regulation, and the device or machine is one of the following:
(A) A device or machine primarily designed for use by individual consumers (including voting machines);
(B)
A motorized land vehicle; or
(C) A medical device designed for whole or partial implantation in patients or a corresponding personal monitoring system, that is not and will not be used by patients or for patient care.
(ii) For purposes of this exemption, “good-faith security research” means accessing a computer program solely for purposes of goodfaith testing, investigation and/or correction of a security flaw or vulnerability, where such activity is carried out in a controlled environment designed to avoid any harm to individuals or the public, and where the information derived from the activity is used primarily to promote the security or safety of the class of devices or machines on which the computer program operates, or those who use such devices or machines, and is not used or maintained in a manner that facilitates copyright infringement."
The changes discussed is not for good-faith security research, so this exemption does not apply in this case.