With a brand-new smartphone – and a new brand – BlackBerry (neé Research in Motion) has embarked on a critical reboot aimed at restoring the fortunes of the company that sparked the mobile revolution.

RIM has been left for dead. For years it hasn’t been able to shake off the stink of irrelevance as the iPhone proved that apps were more important than a physical keyboard, and that mobile “push” e-mail wasn’t rocket science. It endured brand-damaging outages to its private network while competitors crowed that their reliance on a public network was far more stable.

Now the company is reinventing itself in a last-ditch effort to survive. In a press conference yesterday, it announced that it had changed its corporate name to “BlackBerry” to better identify with its iconic product. Meanwhile, it has dramatically upgraded that product after a two-year effort that resulted in new phones designed from scratch and powered by what would be a major mobile operating system: QNX.

BlackBerry’s new smartphones, the multi-touch Z10 and the Q10 – which retains that keyboard some people still swear by — may be the company’s last best hope. I’ve had the Z10 for only a few hours, but if anything can rekindle our romance with RIM, this is it. These BB10 phones are a gambit – not a gamble. (I’ll be doing a full “Go Bag” review with the road warrior in mind in the coming weeks).

Most of the attention is being heaped on the Z10, as demand for smartphones with physical keyboards is the exception rather than the rule. If it manages to make a dent in a world now run by Apple and Samsung — which together had 51 percent of the world’s smartphone market share in the last quarter of 2012 — it will mark one of the great turnaround tales in the history of tech, comparable even to Apple’s Phoenix-like rise from the ashes in the late 1990s.

Not so long ago, Research in Motion ruled the world. I owned one of its first devices, a RIM 857, which did e-mail like nothing else, and just about nothing else. But that device was a vision of the future in the days before smartphones. The “CrackBerry” was a road warrior’s most potent weapon and most impressive coat of arms.

Soon enough, RIM added phone and Web browsing to its devices, and BlackBerrys became an enterprise play: The company could make one enterprise sale and have thousands of new activations in business and government. The iPhone begat a new trend, “Bring Your Own Device,” threatening the BlackBerry’s hold on corporate accounts. The balance of power shifted. Under BYOD, workers now happily buy their own phones, and companies happily support them instead of creating a mobile IT division. It’s a win-win — for everyone but RIM. In perhaps the most crushing BYOD rebuff to the BlackBerry, Yahoo! last September dropped its enterprise account and let its employees use pretty much whatever they wanted – except a BlackBerry.

The good news is that it’s a great time to be in the smartphone business. They clearly are replacing feature phones as the dominant mobile device. According to research firm IDC, smartphones had their best quarter ever at the end of 2012, accounting for 45.5 percent of all mobile phone shipments. Even though the biggest players own most of that, there’s still plenty of business to be had. “The high-growth smartphone market, though dominated by Samsung and Apple, still presents ample opportunities for challengers,” said IDC senior research analyst Kevin Restivo.

The bad news is that we have become very sophisticated. We expect features and ease of use and for our phones to overlap rather than augment our other digital devices — what I call the holy trinity of phone, tablet and laptop. In addition to Apple and Samsung, Google (with Motorola Mobility) and Microsoft (with Nokia) have deep pockets and can wait for the market to come around to them.

RIM — excuse me, BlackBerry — doesn’t have that much leash. It is unprofitable (though debt-free) and has only 2.6 percent of the world market.

The BlackBerry Z10 got mostly positive initial reviews, but investors are not seeing the positives yet. That may be because the new phones won’t be on sale in the United States until March. (They go on sale in the UK today and in Canada in a few days.)

Fair or not, good enough isn’t good enough anymore for a smartphone. We evaluate mobile phones now by how good they are at being pocket computers, not by call quality and battery life.

The Z10’s app store launches with an impressive 70,000 apps, but it is missing some big names and even that number is only about 10 percent of what’s available in Apple’s App Store. But the real question is whether app developers will now flock to this new platform. In perhaps a portend of things to come, the New York Times, which abandoned BlackBerry last July, was back with a launch-day app.

Among the missing pieces is an equivalent to Apple’s iCloud and Google’s Drive: a cloud-based document creation and collaboration services that can help productivity. BlackBerry is at a disadvantage here: It has no hardware/software ecosystem, unlike its operating system competitors. The Z10 has to do some very heavy lifting on its own. It has to be a phone people want in its own right.

BlackBerry has to not just stop but reverse, the BYOD trend. If it can keep its remaining corporate and government customers in the fold, it has a path to elbow its way into the consumer market — just like the good old days.

One out-of-the box feature may help close the deal with enterprise clients. BlackBerry Balance is a feature that gives IT managers an easy way to secure industrial data on the phone. There is third-party software available to do this on the Apple and Android devices, but a holistic solution can be appealing to risk-averse IT departments.

Desperate times call for bold measures. BlackBerry got the message. In changing its name and its game, it has begun a tricky but unavoidable quest.

R.I.P., R.I.M. Welcome to the new world, BlackBerry.

PHOTO: Ben Stephens, a Blackberry sales manager demonstrates a new Blackberry Z10 to prospective customer Shevek at a branch of UK retailer Phones 4U in central London, January 31, 2013. REUTERS/Andrew Winning