NEW YORK — Motorola Inc. is revamping the Razr cell phone that has defined the company's seesaw fortunes, jamming more technological and user-friendly substance into a handset best known for its looks.

The Razr 2 was unveiled yesterday as the centerpiece to a new phone lineup Motorola hopes will reverse a financial tailspin that's led to the company's first quarterly loss since 2004 and wiped away a third of its stock market value in just half a year.

Executives stressed that, rather than attempting to replicate the smash success of Razr with an entirely new device, the best course is to add features and improve performance with more robust software and hardware.

"The Razr was a double grand slam. These are home runs," Ed Zander, Motorola's chief executive, said in an interview. "If you look at consumer electronics, you don't get to create a product like the Razr every five years."

Zander, who recently fended off a proxy fight by Carl Icahn, said that with a franchise as strong as Razr, all that was needed is to ensure it can satisfy the emerging demand for multimedia and messaging.

To that end, the Razr 2 features big jumps in processor speed and screen brightness, both of which are 10 times greater than the original Razr's. The company also has added a 2-inch display to the outside of the Razr 2, calling it the biggest external screen on a flip phone, so that it can be used more easily as a music player.

The user interface, an attribute often criticized with the original Razr, has been redesigned for easier access to the assorted multimedia functions. The company also is adding a newly developed technology called Crystal Talk to improve phone call quality, which Zander said remains the most basic function of a cell phone.

The Razr 2 will be introduced in Asia in July, and elsewhere later in the summer. The company did not name the cell phone companies that will be featuring the device, which will come in versions compatible with the two leading wireless technologies.

Despite all the focus on the Razr 2's innards, the device is in fact 0.08 inches thinner than the original Razr.

Motorola also announced the availability of a new handset, the Moto Z8, and a new version of the Q smart phone with a full keyboard. Both the Z8 and the Q9 were unveiled in February at a trade show in Barcelona.

The Z8, which company executives refer to as the "media monster," will launch in June in Europe. The handset, a slider, has generated some buzz with a design feature: When the screen slides up to reveal the keypad for a call, the phone bends slightly to sit more comfortably against the face — like a clamshell handset.

The Q9 is going on sale immediately in Italy and will reach other markets around the world over the summer.

Thanks to the popularity of the original Razr, Motorola until recently had been on a two-year hot streak. Then it aggressively cut prices of Razrs and other high-end phones, especially in emerging markets, to boost market share. Profits dropped steeply.

Shares of Motorola fell 24 cents, or 1.3 percent, to $17.92 yesterday.