Repair is legal under copyright law. The Digital Millennium Copyright Act of 1998 (DMCA) has a whole section (Section 117) affirming it is legal to backup and restore software for the purposes of repair. This is why makers of application software and operating systems are not impacted by Right to Repair.
The US Senate requested a study of the impact of copyright law on repair in 2015 -- and the report was released in December of 2016. In that study the USCO found that while many consumers believed they might be in violation of copyright law if they made their own repairs, they are not. Even if a consumer signs an "End User License Agreements" (EULA) giving up their existing legal option of independent or self-repair, the OEM can only pursue the consumer for breach of contract.
Firmware Fixes aka "Updates": The real purpose of "updates" is not to deliver free new features, but to fix errors in the original code. It is therefore essential that these "Updates" be widely available to all customers without cost and for as long as possible. The update function is now so common that very damaging changes are being made to consumer property without disclosure -- such as the now famous "Error 53" and "Batterygate".
It has been our philosophy that firmware belongs to the hardware as part of the purchase. If there are defect corrections—they should be entitled to the Serial Number in the same manner as motor vehicle Recalls (voluntary and required) are entitled to the VIN. We see no evidence that this shouldn’t apply generally. We advocate for this relationship throughout out activities.
DRM - Section 1201. This section allows manufacturers to encrypt access to firmware in order to block access to functions that might enable making illegal bootleg copies of copyrighted media. Repair access is also blocked as a consequence of this Section. The USCO studied the impact of Section 1201 on repair and concluded that repair and maintenance should not be restricted by Section 1201, except for equipment where they believe their remains a piracy risk of making illegal copies.
Every 3 years the Copyright Office hears legal arguments for granting exemptions to this section and if granted, the exemption expires again in 3 years. The process is clearly burdensome and DMCA Reform Advocates have long recommended changes to make the process less difficult and the exemptions longer lasting. The Entertainment Software Alliance (ESA) fights vigorously to protect content, which is their forte, but we're not satisfied that it is reasonable to block repair in order to block making illegal copies of computer games and movies.
Right to Repair in states is entirely separate from this process.
Tinkering or Software Hacking: Under current copyright law, tinkering is legal, provided that the equipment is not already protected by Section 1201. Tinkering is referred to as "Hacking" with the software community, but is often confused with illegal hacking by consumers and legislators. We ask our supporters to please try to avoid using the word "Hacking" and suggest the term "customization".
The vast majority of products are already legal to tweak, customize and modify for inter-operability under current law.
Illegal Hacking: Hacking illegally to gain access to personal data, access networks or other bad deeds is just that - illegal. Repair is not hacking, and repairing equipment does not make illegal software hacking more or less difficult or legal.