In a blurb on the cover of Mark Meadows’ new book, Donald Trump calls the former congressman a “great chief of staff – as good as it gets” and predicts “a great future together”. The former president has also promoted the book to his followers.

Now the book is in the public domain, however, the former president reportedly thinks it is “garbage” and that Meadows was “fucking stupid” to write it.

Influential members of the House committee investigating the deadly Capitol attack, meanwhile, have said Meadows may have undermined his own defence when seeking to block their inquiries.

The Chief’s Chief will be published next week. This week, the Guardian broke the news that according to Meadows, Trump tested positive for Covid three days before the first presidential debate with Joe Biden in September last year.

Meadows also details how that test, like another which came back negative, was covered up. Trump eventually announced a positive test on 2 October, the day he was admitted to hospital in Maryland. The White House said that positive result was announced within an hour.

This week, amid huge controversy over whether Trump had endangered not only Biden but the White House press corps, debate staff, the families of fallen US service members, businessmen and more, Trump called the Guardian report “fake news” – a judgment with which Meadows, bizarrely, agreed.

But outlets including the New York Times and the Washington Post confirmed the cover-up.

Late on Friday, the Daily Beast cited three anonymous sources as saying Trump had spent “an inordinate amount of the past few days privately railing against Meadows, the revelation in the memoir, and, of course, the extensive media coverage of the matter”.

Trump, the Beast said, was now “aggressively scolding” his former chief of staff – whose book is filled with effusive expressions of loyalty – and had said he did not know the “garbage” about the positive test would be included in Meadows’ memoir.

A source close to the ex-president, the Beast said, said he “bemoaned that Meadows had been so – in Trump’s succinct phrasing – ‘fucking stupid’ with his book”.

The Beast also reported that Meadows was horrified by the turn of events.

“He thought Trump was going to love it,” the website quoted a source as saying.

Meadows may not love what may be coming his way from the House committee investigating the Capitol attack – also as a result of his book.

The Guardian obtained Meadows’ book the same day he agreed to cooperate with the panel, under threat of a charge of contempt of Congress.

But though Meadows’ discussion of 6 January is highly selective and seeks to play down the attack – which as the Guardian first reported he claims was carried out by a “handful of fanatics” – it could yet prove important.

Like other Trump aides and Trump himself, Meadows has claimed executive privilege, covering communications between a president and his staff, shields him from scrutiny by the select committee.

Adam Schiff of California, the chair of the House intelligence committee and a member of the 6 January panel, told Politico: “It’s … very possible that by discussing the events of 6 January in his book … [Meadows is] waiving any claim of privilege.

“So, it’d be very difficult for him to maintain ‘I can’t speak about events to you, but I can speak about them in my book.’”

Jamie Raskin of Maryland, another Democrat on the panel, said: “You can’t assert a privilege that you have waived by virtue of your other actions.”

Bennie Thompson of Mississippi, the committee chair, told reporters he had seen coverage of Meadows’ memoir.

“Some of what we plan to ask him is in the excerpts of the book,” Thompson said.