According to Business Insider, parts of the excerpt says that Phil Schiller, a top marketer and senior vice president at the company, fought to have a physical keyboard on the first iPhone, much like one on a Blackberry. The expert goes on to say that late Apple CEO Steve Jobs didn’t approve of the idea, and told Schiller to get with “the program or get the f–k out.”

Business Insider reports that the stories about Schiller came from on-the-record quotes, namely from former Apple (AAPL) employees like Tony Fadell. Fadell once headed the iPod division of the company.

In a tweet, Schiller has since denied the idea of a Blackberry-like keyboard:

https://twitter.com/pschiller/status/874714380058763264

Fadell, too, has responded, asking Merchant to “correct the record.”

I respect @pschiller as a colleague & friend. The story about him is not true. Have asked writer to correct the record. https://t.co/87BkZGcHSi

— Tony Fadell (@tfadell) June 14, 2017

As Business Insider notes, Fadell’s tweet is somewhat ambiguous because it doesn’t clarify if he actually said the quotes attributed to him, or if he was misquoted.

Despite the backlash, Merchant has stood his ground. In a statement to Business Insider, Merchant said: “I conducted dozens of interviews with current and former Apple employees involved in the iPhone project while researching this book, including with Tony Fadell. I had no reason to believe his detailed account of the debate over input technology for the iPhone was untrue.

“Parts of this story were corroborated elsewhere,” Merchant continued. According to Business Insider, he added that he had another source with direct knowledge confirm the anecdote. “That’s all I can do in giving an oral history is talk to the people that were there. I asked Apple multiple times for an interview. It’s not an attack on Phil Schiller, I’m just reporting on what people have said,” he said.

A spokesperson for Apple was not immediately available for comment when contacted by Fortune.