Eight lawsuits claim Apple Inc has defrauded iPhone users by slowing devices without warning to compensate for poor battery performance.
A week after the company opened up about the year-old software change, the lawsuits have been filed in US District Courts in California, New York and Illinois
The tweak may have led iPhone owners to misguided attempts to resolve issues over the last year, the lawsuits contend.
All the lawsuits seek class-action to represent potentially millions of iPhone owners nationwide.
Apple did not respond to an email seeking comment on the filings.
The company acknowledged last week for the first time in detail that operating system updates released since "last year" for the iPhone 6, iPhone 6s, iPhone SE and iPhone 7 included a feature "to smooth out" power supply from batteries that are cold, old or low on charge.
Phones without the adjustment would shut down abruptly because of a precaution designed to prevent components from getting fried, Apple said.
One of the lawsuits, filed Thursday in San Francisco, said that "the batteries' inability to handle the demand created by processor speeds" without the software patch was a defect.
Some of the lawsuits claim that users could have bought a new phone, thinking the computer processor was too old when the true cause was a sluggish battery that could be easily replaced.